Pro-European MPs in the two major parties share a complaint: that the other side is asking them to make a fruitless sacrifice.

On the Labour side, pro-single market MPs despair that the likes of Anna Soubry and Nicky Morgan will talk a good game on the importance of as soft as possible an exit from the European Union, before voting with the government. As one MP puts it, “they are loud in the Times, and quiet in the Chamber”. That means, or at least so Labour MPs argue, that they have a painful internal fight over Brexit to no good end.

On the Conservative side, they argue that because a significant bloc in the parliamentary Labour Party are committed to a drastic breach, it is they who are being asked to vote against their own government and make problems for themselves, while their own votes are, in any case, cancelled out by Labour MPs voting for the hardest possible exit. (Although Jeremy Corbyn has whipped Labour MPs to vote against the European Union Withdrawal Bill, some committed Eurosceptics will likely defy the whip to vote with the government.)

The coming vote on the second reading of the Withdrawal Bill is significant because it will heighten that argument and give us some idea how plausible it is that this new hung parliament can soften or stop Brexit.

The point of the Withdrawal Bill is to end the automatic link between European and British law by repealing the European Communities Act, under which EU law is transposed onto British law. In order to ensure a measure of continuity, all currently existing European law will be incorporated into British law.

So far, so uncontroversial. Voting down the Withdrawal Bill wouldn’t stop Britain leaving the European Union. All it would do is add to the confusion about how British law works after Brexit. The cause of controversy are the so-called Henry VIII clauses, which allow ministers to amend European laws and regulations through ministerial fiat and statutory instruments, neither of which incur the detailed parliamentary scrutiny of a full-blown act.

That’s why Labour has vowed to vote against the bill at second reading. But the government should avoid defeat easily, because pro-European Conservatives are going to vote with the government at this point.

Why? Their argument is that voting against a bill at second reading tends to be reserved for when the objection to a bill is philosophical. (That’s one reason why the Lords, a revising chamber, rarely divides at second reading.) As the principle of ensuring legal clarity is not in contention, but the scale of the powers granted to ministers is, they believe the appropriate time to vote against the bill is at committee stage.

That means that this bill will settle a lot of arguments. Labour’s vote at second reading will demonstrate how many of the party’s MPs can be rallied around a softer Brexit position – Conservative votes at committee stage will reveal how numerous and how serious pro-European Tories are.