Nicky Morgan is Chair of the Treasury Select Committee, a former Education Secretary, and MP for Loughborough.

“Politics is the art of the possible” is an important statement of realpolitik, and we shall see if enough MPs believe in it on Tuesday. For on that day, the Commons will conduct its most important vote for decades – and easily the most important that those of sitting on the green benches at this moment in history have ever experienced.

After a blissful fortnight almost free of EU-related news, there was a hard return to Planet Brexit last week in Westminster and beyond. Government defeats, Parliamentary precedent being overturned, ugly protests outside Parliament and the resumption of the debate on the Withdrawal Agreement all meant that Brexit was back in our social media feeds, front pages and inboxes with vengeance. However much we want to talk about something else (and the public certainly want us to talk about almost anything else), it is dominant and overpowering.

Brexit matters. How it turns out will shape the UK’s place in the world, our relationship with our closest neighbours and the development of our economy, politics and the unity of our country for decades to come.

Many MPs have very strong views on it and on the type of Brexit that they will accept. But those views have changed over the course of the last 30 months. And changing your mind is not something to be criticised when the subject matter is so important.

As set out in my last Conservative Home column, I firmly believe that it is for MPs to decide the outcome of Brexit and that a second referendum would be a very bad idea. But it follows that MPs have to make a majority decision.

I also believe that a No Deal outcome to Brexit would be an equally bad idea. And I voted to signal so by supporting an amendment tabled by Yvette Cooper last week. But to avoid a No Deal outcome I accept that a deal has to be put in place. That is why I’ve been clear that I will support the Prime Minister’s draft Withdrawal Agreement and, if that doesn’t succeed, then a Common Market 2.0 (also known as Norway Plus) route.

Supporting the Withdrawal Agreement would also prevent several other things – such as an immediate vote of confidence tabled by Jeremy Corbyn and the fear of a truly socialist government taking over. Over the weekend, there was some breathless speculation about radical changes to established Commons procedures to block or delay Brexit. These reports might be misleading or wrong.  But a sure way of avoiding either is to pass the Prime Minister’s deal on Tuesday.

There is no doubt that the draft Withdrawal Agreement is not perfect. But leading Cabinet Brexiteers such as Penny Mordaunt and Andrea Leadsom accept it. And as Michael Gove put it in the Commons last week: “All of us might have a perfect version of Brexit—a change here, an alteration there—but we all have to accept our responsibility next Tuesday to decide whether we are going to honour that verdict. Are we going to make the perfect the enemy of the good? …That is why, after long reflection, I have decided that we must back this agreement.” Can MPs opposed to it not agree to do do the same?  If their colleagues, such as George Freeman, Trudy Harrison and Jim Fitzpatrick can admit that they are changing their minds, then why won’t others follow suit?

I hope, in the short time left before the vote, that other MPs will think very long and hard about what a defeat for the Prime Minister’s draft deal will mean. Pledging to vote a particular way to an outside campaign group does not bind an MP. Changing our minds can be a good thing – and it is what debate in the Commons and conversations with our constituents should bring about. Doing the right thing in the wider national interest is what we should all be about.