What will be noted most in Brussels & EU27 is not that the amendment passed, but that May supported it.
She agreed the Backstop (twice); she proposed its form; she asked for & got their help in selling the WA; she promised she'd be able to.
Then she chucked it under a bus. 1/
Most seem to have conveniently forgotten that the EU27 line that this is the Withdrawal Agreement, the only Withdrawal Agreement available, an that it will not be re-opened was in response to May's need to force her own MPs to agree it.
They also forget that the reason it is UK-wide is because May requested it was that rather than NI-only, as she wrongly thought it would placate the DUP and BritNat Tories. Many of EU27 preferred NI-only as they thought it was UK getting Future Relationship concessions easily. 3/
It's one thing for Parliament to throw concessions and assistance back in EU27's face. They get the difference between Government and Parliament. It's quite another for the PM who they gave the requested concessions and assistance to, and who promised it'd be fine, to do so. 4/
She, and this Cabinet, will never be trusted again by EU27 leaders. Future Relationship negotiations will be conducted in a trust- and goodwill-free zone. Requests for concessions will be dismissed. Assistance will not be forthcoming. UK perceptions ignored. 5/
Even if she does eventually get the WA through, the UK will be entering a world of pain in negotiations as a result of UKGov's earlier conduct and breaches of trust. EU27 will put options on the table. UK will decide to take or leave them. 6/
Those MPs who don't want this, who rightly don't believe they will have any real say, and who know they'd have to accept whatever comes out of the process or face a new No Deal cliff-edge without the option to revoke, need to act now. 7/
The choice for them is the deal, and a world of pain and helplessness for 2-4 years then swallowing whatever they're given; a world of pain now through no deal; a way out of this through an extension & ref; or more waiting and an emergency revocation in March to avert no deal. 8/
And that's if there'd be time (which there may well not be) to legislate (which may be needed) for an emergency revocation by then. Unless you want to rely on the PM doing the right thing at that point.
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