Withdrawal Agreement Meaningful Vote
Dewan and Spirling (2011) develop a theoretical argument for why opposition parties are able to act coherently despite the temptation of some of their MPs to support government policies. The source of such strategic opposition is that if the opposition votes against the government en bloc (and no opposition MPs deviate from it), it can force the government to propose a more moderate policy than usual, and this result is in the interest of all opposition MPs. Since the DUP would certainly vote against it for the third time, it would have taken a major rebellion within the Labour Party to create a majority for the withdrawal agreement, even though most of the Conservative backbencher rebels would have changed their votes. Johnson`s change of mind was therefore never likely to make a significant difference in the outcome of the vote. Third, the Brexit situation offers a unique opportunity to measure voter preferences, as we know globally how voters voted in each constituency in the 2016 referendum. Footnote 14 We code the variable SHARE OF VOTE FOR LEAVE as the proportion of electors in each electoral district who voted for leave in the referendum. Table 1 shows the distribution of MPs` votes between the three significant votes by party (Panel A) and for the Conservative Party between leading and backbenchers (Panel B). From this data, we see that a number of factors contributed to May`s defeat. The Democratic Unionist Party (DUP) – a socially conservative and pro-Brexit Northern Irish party – which had agreed to support the Conservative government (after losing its majority in the 2017 general election) rebelled because it believed the Withdrawal Agreement treated Northern Ireland differently from the rest of the UK (in the context of the so-called Irish backstop problem).
Very few pro-Brexit MPs from the centre-left opposition Labour Party have backed the government. Footnote 5 The centrist Liberal Democrats (LD) and the centre-left Scottish National Party (SNP) unanimously rejected the government, but this opposition was expected. By far the most important factor in May`s defeat was the enormous scale of the rebellion by her own backbenchers. Prominent MPs with government posts, on the other hand, went to the line and none of them rebelled (Table 1, Table B). During the debate, the government assured potential Conservative rebels that they would address their concerns in a new amendment that the Lords should consider. It was thought that the concession offered by the ministers would include a new parliamentary motion if the Brexit agreement was rejected by MPs and colleagues, which would open the door for MPs to take control of the negotiations if ministers in Brussels fail to reach an agreement.  The concession meant that the government received 324 votes to 298, a majority of 26.   Broader legislative institutions and party structures help shape the costs and benefits for politicians who deviate from the party line, as well as the constraints faced by party leaders in creating party coherence (Krehbiel 1993). .