Twenty-Six Defecting MPs, One Special Session: Delimitation by Raw Arithmetic

After losing in April, the government is gathering numbers, not consensus, for a seat-expansion that reshapes India's federal balance.

On 17 April 2026, for the first time in twelve years, the Modi government lost a vote on a constitutional amendment. The Constitution (131st Amendment) Bill needed two-thirds of the members present and voting in the Lok Sabha. Of 528 members who voted, 298 supported it and 230 opposed it. It needed about 352. It fell short by more than fifty votes. Within minutes, Union Minister Kiren Rijiju withdrew the companion Delimitation Bill and the Union Territories Laws (Amendment) Bill, and Home Minister Amit Shah said that India's women would not forgive the opposition.

Six months later, the government is back. Government sources have said that the Centre is likely to convene a special session of Parliament later this month to take up the same package: constitutional amendments on delimitation and women's reservation. They also say the Centre now has the numbers. What has changed in six months is not the Bill. What has changed is the arithmetic. Reports say 20 Trinamool Congress MPs and six Shiv Sena (UBT) MPs have switched to the ruling side. The government is also talking to the DMK, which has broken with the Congress after the Tamil Nadu elections and left the INDIA bloc.

This is a moment that deserves a long, careful look. A constitutional amendment on delimitation decides how much each Indian state counts in the national legislature for a generation. It is the most federal question there is. And the way the government is going about it, by collecting votes instead of building agreement, says a great deal about how it sees the Constitution.

What the April Bill actually proposed

To understand the stakes, start with what the failed Bill would have done.

First, it would have raised the size of the Lok Sabha from the present 543 seats to an upper limit of 850. Second, it would have allowed delimitation, the redrawing of constituencies and the redistribution of seats among states, to be carried out using the 2011 Census, without waiting for the 2027 Census to be completed. Third, it would have changed Article 334A so that the one-third reservation for women in the Lok Sabha and state assemblies could take effect in time for the 2029 election.

The women's reservation itself was not new. The Nari Shakti Vandan Adhiniyam, the 106th Constitutional Amendment, was passed in September 2023, with wide support from all parties. But the law tied its implementation to delimitation after the first census held after 2026. That meant women would not get a third of the seats in 2024, and, on the existing schedule, probably not in 2029 either. The 2027 Census has a reference date of 1 March 2027, and it is unlikely that a delimitation exercise based on that census could be completed before the 2029 elections.

The government's April plan was to move faster. The opposition's objection was not to women's reservation. It was to the way the government had tied it to a bigger, more controversial change. The opposition's position, repeated through the debate, was to separate the two: implement women's reservation now, and discuss seat redistribution separately, in the open.

Why the freeze exists

The political battle over delimitation is old. In 1976, during the Emergency, the Constitution was amended to freeze the number of seats given to each state in the Lok Sabha, based on the 1971 Census. The reason was fairness. States that were doing well at lowering their population growth, mostly in the south, should not be punished with fewer seats than states where population was growing faster. The freeze was extended in 2001 by the 84th Amendment, until the first census after 2026.

That deadline is now close. The next census is under way. And the question of what happens when the freeze ends is the central one.

The logic of delimitation is simple. A constituency is meant to have about the same number of voters as any other. If one state's population grows much faster than another's, then, if seats are redistributed according to population, the faster-growing state gains and the slower-growing one loses. In India's case, the faster-growing states are mostly in the north and centre. The slower-growing ones are mostly in the south and some in the northeast.

What the numbers show

State-by-state tables have been published on what delimitation using 2011 Census data would mean. They show two scenarios.

In the first, the Lok Sabha stays at its present size of 543. Seats are then shifted among states by population. Tamil Nadu would drop from 39 seats to 32. Kerala would fall from 20 to 15. Andhra Pradesh would fall from 42 to 38. At the same time, Uttar Pradesh would rise from 80 to 89, Bihar from 40 to 46, and Rajasthan from 25 to 30.

In the second scenario, the House is expanded to 850. Then nobody loses seats in absolute terms. Andhra Pradesh would rise from 42 to 56. Bihar would jump from 40 to 69. Haryana would go from 10 to 17. Assam would go from 14 to 21 and Chhattisgarh from 11 to 17. Using this kind of expansion, the government has argued that the south would not lose out. In the Lok Sabha debate, the government said the seats of the five southern states would rise from 129 to 195, and that their share would go from 23.76% to 23.87%.

That claim is worth looking at closely. A share of 23.76% rising to 23.87% is a rise of 0.11 percentage points. In other words, under the government's own calculation, the south's share barely changes. It is protected only if the House is expanded to a very large size and the expansion is done in a way that holds shares almost constant.

But the Bill itself did not guarantee that. It did not lay down the formula. According to PRS, the Delimitation Commission was not defined in the Bill, and the details of how seats would be allocated were left open. The opposition was asked to vote for a constitutional amendment that opened the door to a large change, with the formula to be decided later by a body whose composition and powers were not spelled out.

That is the real issue. It is not whether the government's numbers add up in a speech. It is whether the guarantee is written into the law.

A promise made in a speech can be forgotten. A guarantee written into the Constitution cannot. The south is entitled to the second.

The political arithmetic

Now to the part that changes this month: the votes.

The Lok Sabha has 540 members at present, because of vacancies. The NDA has a majority. But a constitutional amendment needs two-thirds of those present and voting, which comes to roughly 360 seats if every member votes. The NDA falls short of that on its own.

What has happened since April is that members of other parties have moved to the ruling side. Reports say 20 Trinamool Congress MPs and six Shiv Sena (UBT) MPs have switched. The government has also reached out to the DMK, whose break from the Congress after the Tamil Nadu elections has changed the picture, as well as to some smaller opposition parties.

Several things should be said about this.

First, the details are thin. The reports are sourced to government sources. We do not know the legal form of the switches. India's anti-defection law, the Tenth Schedule, allows a party's legislators to merge with another party if two-thirds of them agree. Whether those conditions were met for each case is a question the Speaker's decisions will answer, if and when they are made public. Members should not be able to move in a way that wins votes for a constitutional amendment while the legal questions remain open.

Second, the figures raise a basic question about consent. A constitutional amendment on a matter this important is supposed to reflect wide agreement among India's elected representatives, not a count of how many members could be moved across the floor in six months. If the amendment would have failed in April and passes in October only because 26 members changed sides, then the Constitution is being amended by a different set of people than the voters chose.

Third, the political context is not neutral. The special session is being talked about while opposition protests over the voter-roll revision and the Chief Election Commissioner are at their peak. A government that wants a quiet debate on a matter of great consequence would not choose this time. A government that wants the news cycle filled with something else might.

Who gains, and who loses

It is useful to ask a plain question: who benefits if the amendment passes in the form proposed in April?

The first answer is the party that is strongest in the north and centre. An expansion of seats in northern, central and western India would win the BJP massive popularity in the Hindi heartland states. That is a political fact. If Bihar goes from 40 seats to 69 and Haryana from 10 to 17, those are states where the BJP is strong and where voters would see a large expansion in their own representation. The party that proposes the expansion stands to gain from it.

The second answer is women, in principle. Women's reservation is a real and long-overdue reform. But there is a catch. If the reservation is tied to a delimitation that is contested, then women's representation depends on the success of a political fight about something else. The opposition's point, that the two should be separated, is not an attempt to block women. It is an attempt to make sure that women's reservation does not become hostage to a seat-allocation deal.

The third answer is the states that would lose relative weight. Tamil Nadu, Kerala, Andhra Pradesh, Telangana and Karnataka have, over decades, been rewarded by India's own national policy goals. They lowered their population growth, which was exactly what the government of India asked states to do. A formula that gives them a smaller share, or that depends on a promise instead of a guarantee, punishes the states that did what they were told.

There is also a deeper federal question. Seats in the Lok Sabha determine more than representation. They shape who forms governments, which regions matter in elections, and how much attention each state gets in national policy. A change in the balance can change the country's politics for decades.

What the DMK's move means

One of the most important political facts is the role of the DMK. The party's break from the Congress after the Tamil Nadu elections, and its exit from the INDIA bloc, has made it a target of the government's outreach.

For the DMK, the stakes are very large. Tamil Nadu is the state that has most consistently raised the fear that delimitation will punish the south. Its leaders have said so for years, and in 2024, chief ministers of southern states held a dharna at Jantar Mantar over fair devolution of central taxes. A party with that record cannot easily support an amendment without a written guarantee that the south's share will be protected.

If the DMK does support the Bill, the public should ask what it was promised, and whether the promise is written in the Bill. If it does not, the government's calculation changes. Either way, the DMK's choice is a test of whether regional parties will treat this as a bargaining chip or as a matter of principle.

The process: how the government is going about it

Setting the content aside, the process deserves attention.

The Monsoon Session of Parliament ended on 13 August but has not been prorogued. That technical choice leaves room for the government to call a sitting at short notice. A week's notice could be given. The dates are expected to be fixed around the 12th BRICS Parliamentary Forum, which will be held at Samvidhan Sadan on 26 and 27 October.

A special session called at a week's notice, on a constitutional amendment that was defeated six months ago, raises several questions about the process.

Will the Bill be sent to a parliamentary committee, where states and experts can be heard, or will it be pushed through in two or three days, as in April, when the special session ran from 16 to 18 April? Will the text be published in advance, with the seat-allocation formula? Will the Delimitation Commission's composition and powers be spelled out? Will chief ministers and state legislatures be consulted? Will the 2027 Census data be used, or the 2011 Census?

These are the minimum questions for a change of this size. If they are not answered before the session, the vote will take place in the dark.

The government's best argument

It is only fair to state the government's strongest case.

It would say, first, that women's reservation has waited far too long. A law passed in 2023 with all-party support should not have to wait until the 2030s. If delimitation is what stands in the way, then delimitation must be done quickly.

It would say, second, that the Lok Sabha has had the same number of seats since 1977, based on the 1971 Census, and that India's population has more than doubled since then. A House of 543 members, each representing an average of about 25 lakh people, is too stretched. Many democracies have far smaller constituencies. Expanding the House to 850 would bring representation closer to people.

It would say, third, that the expansion is designed to protect the south. The seat counts of every state would rise. No state would lose a seat. And the south's share would remain about the same.

These are serious arguments. A good-faith government could make them and expect a hearing.

But they are weakened by the way the government has acted. If the aim was to build agreement, the government could have sent the Bill to a joint committee, published the formula, and given the south a clear guarantee. Instead it brought the Bill in a special session, lost, and is now working on the numbers.

What a fair approach would look like

There is a way through this, and it would not take long.

First, separate women's reservation from delimitation. Implement the one-third reservation in a way that does not depend on seat redistribution, for example by rotating reserved seats within the existing structure for 2029. This would give women their seats without prejudging the larger question.

Second, if delimitation and expansion go ahead, write the guarantee into the Constitution. Say, in the text of the amendment, that no state's share of Lok Sabha seats will fall below its current share. This is what the government says it intends. It should be willing to put it in writing.

Third, set up a transparent Delimitation Commission. Define its composition, include judges and experts, give states a formal role, and publish its draft before it is final.

Fourth, use a committee. Send the Bill to a joint parliamentary committee, with public hearings and state submissions, for a fixed period of a few weeks.

Fifth, be open about the numbers. Publish a table showing, state by state, what the seat allocation would be under the proposed formula, and what it would be under alternatives.

Sixth, address the defections. The Speaker should publish the legal basis on which each member's change of party was recognised, so that the vote is not clouded by doubt.

If the south's share is truly safe, the government should have no objection to writing it into the Constitution.

What the public should watch

In the coming days, three signals will matter.

The first is the notice and the text. If the government calls the session and publishes the Bill with a clear formula and a guarantee, that is a good sign. If the Bill is short and the details are left to a commission, that is a bad sign.

The second is the DMK and other regional parties. If they demand and win written guarantees, the south may be protected. If they support the Bill without one, the question for their voters will be what was promised.

The third is the opposition's unity. In April, the opposition defeated the Bill together. If it is split now by defections and bargains, the government may get its number. If it holds, the Bill may fail again. In that case, the government will have wasted a special session and shown that votes cannot be assembled by arithmetic alone.

The bottom line

A constitutional amendment is not an ordinary law. It is a promise between regions of a diverse country about how power will be shared. The Constitution's framers made it hard to change for a reason. They wanted changes of this kind to pass only when a very wide group of Indians agreed.

The government lost in April because it could not show that agreement. It is now trying a different route: instead of persuading, it is counting. It may succeed. Twenty-six switched members, a few regional parties and a week's notice may be enough to reach the number.

But a number is not a consensus. If the amendment passes on that basis, with the formula unwritten and the south's share resting on a speech, then the country will have changed the balance of its federation by a margin that no one chose in an election. Women deserve their seats. The south deserves its guarantee. And the Constitution deserves better than to be amended by arithmetic.