But there is a critical difference. Labour is no longer rejecting the Prime Minister’s Brexit deal. Instead Corbyn is now offering his own deal: accept our changes to the Political Declaration, bind yourself to them in UK law and we will support your Withdrawal Agreement.
The Prime Minister had two options: pivot backwards to appease her backbenchers or pivot across the House to a softer Brexit.
She is currently pursuing the first, attempting to persuade the EU to modify the backstop enough to hold her party together. That is why she indulged the “Malthouse compromisers” with their Alternative Arrangements Working Group and requested that the EU reopen the Withdrawal Agreement.
Prospects of anything other than a firm rebuff from Brussels is dim – for now at least. But for a Conservative Prime Minister, an option that secures the support of your own party is always going to be more appealing than making common cause with the Opposition.
But as the Prime Minister bangs her head into a brick wall in Brussels, she may be tempted to look in another direction.
The Corbyn letter gives the appearance at least of offering a plausible way forward. It does not involve reopening the Withdrawal Agreement but focuses instead on the Political Declaration – something the EU has said it was willing to look at again.
Accepting Corbyn’s demands requires a shift in the Prime Minister’s red lines – most notably on a commitment to a permanent customs union. Some of the other conditions require less of a compromise. The Prime Minister has already proposed “close alignment” with the Single Market on goods (though not on services) in her rejected Chequers deal, and she seems to be contemplating whether to concede “dynamic alignment” on Labour standards to secure the support of Labour Leave rebels.
The Norway Plus/Common Market 2.0 advocates in Parliament seem ready to embrace the Labour leader’s move, but that doesn’t mean the EU will rush to embrace the Corbyn plan. A permanent customs union has always been on offer, as might be a “say” (i.e. consultation not decision making) on future trade policy.
Corbyn seems to want full participation in the Single Market – but without clarifying the commitment to free movement. This would require some governance of UK participation in the Single Market and the Government has already made proposals for a Joint Committee and Governing Body and dispute resolutions. The EU will not create “shared institutions” with a non-member state to make decisions.
What is not clear is whether Corbyn wants these all embraced in the Political Declaration. His letter only talks of “enshrining” these negotiating objectives in law before the UK leaves the EU. If he means UK law, then what the EU thinks may matter less than if they need to be attached to a legally binding EU agreement.
Corbyn has already outraged many of the most committed People’s Vote advocates in the Parliamentary Labour Party and this letter may cause trouble with his membership.
But the main impact of the Corbyn letter may be on the mindset of the people who sit behind the Prime Minister. If they are persuaded that without their support she will opt for a Corbyn-style Brexit, many Conservatives could decide their less bad option is to back her deal.