Analysis: Clegg leaves door open for Huhne
Chris Huhne is the third minister to step down from the cabinet since the coalition came in to being in the summer of 2010.
Each occasion has been followed by a mini-reshuffle, and on each occasion it has illustrated the rigid deal between David Cameron and Nick Clegg on who gets what.
The Liberal Democrats are guaranteed a certain proportion of the seats around the cabinet, in return for their support.
Nick Clegg chooses who to propose for the post on offer, David Cameron has the final say.
Some Tories don't like the arrangement, mostly those who expected a top job or those who aspire to one, but that's the politics of the coalition.
But could Mr Huhne, who denies a charge that he perverted the course of justice over a 2003 speeding case, yet make a comeback?
After he announced he would be stepping down to fight his case in court, the deputy prime minister was warm in his praise for his old leadership rival, describing him as "a good friend and a close colleague".
This from the man dubbed "Calamity Clegg" by the Huhne team during the 2007 Lib Dem leadership race.
Intriguingly Nick Clegg has already said Mr Huhne could come back to government if he clears his name.
Mr Cameron did not make the same offer in his letter to Mr Huhne - but his spokesman told journalists who suggested that was significant that they were "over-interpreting".
It may be that the view from the top is that it's best to keep the door open if there's a chance of a cleared Mr Huhne looking to make a return.
The former energy secretary is respected and liked by many among the grassroots of his party. The bulk of his support in the leadership contest came from associations.
They will expect fair treatment for their man as he prepares to fight the charges in court.
There are many if and buts to this story. It could put an end to Mr Huhne's political career.
But if he is cleared, the backbenches are not a place where he is likely to sit comfortably.
In Westminster circles there is talk of another loser in all of this - David Laws.
The MP was one of the most important Lib Dems in the cabinet as the coalition launched but he was forced out within a matter of weeks over his expenses.
There are persistent rumours that he is on the verge of returning. Both David Cameron and Nick Clegg have said publicly that they want him back. But it was not to be this time.
A bigger reshuffle is expected at the start of the summer, as ministers meet the two-year term some were told to expect when they were appointed. That could be the opportunity to bring him back.
It will have to be a like-for-like swap though.
The coalition cabinet numbers are embedded in the agreement between the two parties.
If David Laws is to return he needs another resignation or - far better for all involved - a retirement.