As a call in the Commons for a judicial inquiry into the Iraq weapons row has failed, the crucial political question is now Labour loyalty to Tony Blair.
How far are MPs who privately believe the government did mislead or twist intelligence information prepared to go in supporting him anyway?
With the main opposition parties now all lined up behind the call for an independent judicial inquiry into the political use of intelligence ahead of the Iraq war, the next question is whether Labour rebels could get the 85 or more votes they would need to force such a move.
John Prescott urged loyalty from Labour MPs
Since 139 MPs rebelled against the government just before the war, you might think this would be easy enough. But it doesn't feel that way in the Commons just now.
A vehement "tirade" about the need for loyalty from Deputy Prime Minister John Prescott at a private meeting of Labour MPs produced loud support in the Commons.
There is self-interest here, too. Labour members are now coming to the second half of the Parliament and beginning to think about their own electoral future: perhaps helping paint their leader as a liar isn't a helpful message to be sending out.
In a startling attempt to help Labour people think politically, and to close the shield wall round Mr Blair, the Leader of the Commons John Reid warned of "rogue elements" inside the security forces determined to do down the government.
Labour's folk memory of right-wing spies fomenting treason is emphatically not something Mr Blair would want to revive
His words are uncomfortably reminiscent of the paranoia that swept through Number 10 in the mid-1970s when Harold Wilson became convinced that MI5 was conspiring against him, after a series of burglaries and press leaks.
Most historians now dismiss any serious organised plot, but Wilson was so worried he took to running the taps in Downing Street lavatories before having private conversations, and would point worriedly at light-fittings, implying that they were bugged.
With the Cold War still at its height, the 70s were a very different world.
Labour's folk memory of right-wing spies fomenting treason is emphatically not something Mr Blair would want to revive.
He leans very heavily on the advice of intelligence officers in the new world of global terrorism, and cannot afford to fall out publicly with the security or secret intelligence services.
Avoiding doing so now depends on the results of the two inquiries that are already off and running.
He has given the Intelligence and Security Committee wide promises about seeing draft documents and interviewing intelligence staff: they will probably find out more about the circumstances surrounding the decision to go to war than anyone else.
The question is, will they tell the rest of us?
The ISC is inside the circle of British official secrecy and its reports are censored.
Yet the MPs on it know they have competition, in the shape of the more open Commons foreign affairs select committee, which will meet and take most of its evidence in public.
Both committees too will be looking sideways at Washington where a parallel investigation into the role of the CIA is going on.
None of this will finally answer the biggest questions, such as whether the war has really helped damp down terrorism, or made it more likely; or the extent to which George Bush and Mr Blair had decided to topple Saddam early on.
But if he can answer the charge of doctoring the facts to take Britain to war, the prime minister will be hugely relieved.
It is hardly the political victory parade he hoped for.