What price will the DUP ask in a knife-edge vote?
It can be tough being one of Westminster's smaller parties. Cameron and Miliband tend to hog the headlines and have the muscle of hundreds of MPs behind them.
But when the numbers are tight, attention comes their way. This, as the Tories make a last bid to force through changes to Parliamentary boundaries, is one of those days.
Thus we have heard plenty of talk of the DUP being "in talks" with the Prime Minister over the terms on which its eight MPs could lend their support.
The thorny issue of Sinn Fein's allowances may well have been raised. And we're still waiting for a decision on corporation tax.
Last night Nigel Dodds was giving little away, telling me the party would make its decision today.
The DUP's Westminster leader had previously insisted the boundary review was not discussed, when his party recently met Mr Cameron to discuss the implementation of the military covenant in Northern Ireland.
It was also suggested that the Government could agree to exempt Northern Ireland from the changes in return for the DUP's support - although it's hard to see that being a credible option.
Northern Ireland's representation would be cut from 18 to 16 MPs if the changes come about.
Even if the DUP decides it has overcome its reservations over the Electoral Registration and Administration Bill, it's hard to see how the Government, or more precisely the Tories, can win this.
Nick Clegg has given his word that his party will vote against, rather than simply abstaining, as revenge for the demise of House of Lords reform.
The opposition would number 312 MPs. The Tories plus DUP would come to 311.
Then there's the SNP, which would surely not back the Government on such a pivotal vote with an independence referendum looming, and Plaid Cymru, whose three MPs are expected to vote against. The same goes for the SDLP: its three MPs are expected to oppose the measures.
There's even the possibility of some Tory rebels - plenty are 'losers' from the rejigged boundaries and may plan to abstain or oppose the shake-up.
Turnout will be crucial and the Labour Party is anxiously briefing that the vote will go to the wire.
One thing's for certain: coalition relations will be soured even further after this episode.
One Tory MP warned it would "mark a turning point" in the relationship between the two partners in government.
Now we'll find out which side the DUP will take.