Chris Mason: No 10 buoyant, but not there yet

Downing Street is pleased with how the new Brexit deal for Northern Ireland has gone down so far.

In the House of Commons on Monday evening, there was a blanket of warm words from most MPs.

From a former Prime Minister, Theresa May. From a former Brexit Secretary, David Davis. From Labour. From the Scottish National Party.

But those around the prime minister attach particular significance to two words from the leader of the Democratic Unionist Party (DUP).

Sir Jeffrey Donaldson said the deal amounted to "significant progress." Although he did then sound a note of caution.

But this is where the duvet of positivity about the deal beyond the UK might help Rishi Sunak.

French President Emmanuel Macron said: "I welcome this important decision."

President Joe Biden in Washington described it as "an essential step" and added that he hoped "Northern Ireland's political institutions are soon back up and running."

And the White House added that "the United States stands ready to support the region's vast economic potential."

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Which rather sounds like the prospect of money heading in Northern Ireland's direction, if power sharing devolved government returns.

And the prospect of a visit from President Biden - to mark the 25th anniversary of the Good Friday Agreement in a few months - has long been floated by American diplomats.

On Tuesday, Rishi Sunak will be busy talking up what he sees as his plan's big achievements and the difference it can make.

How, in the coming months, does any resistance or ongoing scepticism from the DUP respond to such a broad range of political and business voices saying the new deal is an improvement?

It's this that gives senior Conservatives hope, in private, that perhaps in the end the DUP will be tempted back into power sharing at Stormont and devolved government will return.

But as this debate plays out, it's worth spelling out a central truth here.

The Windsor Framework is an acknowledgement of a central reality of Brexit. Northern Ireland continues to have a different relationship with the EU than the rest of the UK.

And for as long as governments at Westminster say "no" to closer economic ties with Brussels, that different relationship is guaranteed.

It is a relationship destined to be bespoke, challenging and awkward - juggling a project about borders, Brexit, with an open border between Northern Ireland and the Republic.

While many in Northern Ireland are comfortable with that, some unionists will probably never be.

It is why the path to delivering the ultimate prize of these negotiations, restored devolved government, is so sought after, and so difficult.