The deal at Hillsborough Castle ties the DUP's prospects in with the fortunes of Stormont's power-sharing administration.

It will not be fighting the General Election on a platform of having faced down Sinn Fein demands for the devolution of policing powers.

Instead, it will presumably present itself as having taken tough decisions in the interests of unionism and to move Northern Ireland forward.

That will require the new deal to stick, which means Peter Robinson has an important selling job.

He will enjoy the fact that he kept his MLAs on board this week, despite all the speculation about divisions.

However, some colleagues were hardly rushing to stand shoulder to shoulder with him yesterday.

The first crunch issue is looming, with the new panel on parading given until February 23 to produce a way forward.

Will it contain enough to convince all DUP MLAs to vote for the devolution of policing powers in early March?

The expectation is that the Parades Commission will be replaced.

But the overall balance of power is unlikely to shift significantly towards the loyal orders. When it comes to disputed routes, it will remain messy and complicated, involving local dialogue and some rulings by a Commission-style body.

The Ulster Unionists are in no hurry to give Mr Robinson cover. They have their own electoral interests, plus the scars from all those DUP brickbats over the Good Friday Agreement.

However, Sir Reg Empey is in a delicate position too. The recent mixed messages on unionist unity and the Tory pact could hardly have been sent out at a worse time.

Saying no to this week's deal seems a non-starter. It is supposed to be in the pro-power sharing camp and the TUV has anyway already claimed the ground to the DUP's right.

Sir Reg's pact partner David Cameron will want the deal to work. If he makes it to Downing Street, he will have enough to do without worrying about Stormont.