By Nick Assinder
Political correspondent, BBC News website
For more than two years, the Liberal Democrats had only one question in the front of their minds - what to do about their leader, whoever he was.
The new leader has to start looking outwards
The question now is how on earth the new leader can follow "caretaker Cable" who, during his brief time in the job, has become a bit of a political star, regularly besting the PM in the Commons and bringing weight and experience to the post.
Unlike the last two full-time "real" leaders - and thanks to his non-combatant role in the succession - Vince Cable was left alone to get on with the job of leading.
And that is something both Charles Kennedy, in his later days, and Sir Menzies Campbell, throughout his period in office, were denied by their own MPs.
First it was Mr Kennedy - arguably, in electoral terms at least, the most successful third party leader for almost a century - whose behaviour became the cause of concern amongst the parliamentary party.
He was eventually forced out after confessing to a drink problem, sparking one of the most revelatory, tabloid-filling and distracting leadership contests any party has suffered for decades.
His successor, Sir Menzies, hardly got his feet under the table before his own performance became the source of much internal whispering, which finally grew to full-blown plotting once Gordon Brown "bottled" an autumn election and gave the Lib Dems time to oust him in favour of the younger man many had always wanted.
Sir Menzies spotted the glint of daggers and ambition in his detractors' hands, and decided to throw in the towel, in some exasperation and anger, before they struck.
So, after such a torrid time, during which the party has drifted and its poll fortunes slumped, the new leader faces some pretty hefty challenges.
Probably the first thing he has to do is get a solid grip of his parliamentary party, to ensure there is no more plotting and that his MPs fully unite behind him.
That will mean offering frontbench jobs to some of his rivals, but it may also mean taking a tough line with those who habitually snipe at their leader - and he knows exactly who they are.
But after the past two years, he should be working with the grain on that one.
The next big task will be to turn outwards. After a long and dangerous period of introspection, the party has slipped off some voters' radar - despite Mr Cable managing to grab more than his fair share of positive headlines.
That will mean getting the party's voice heard clearly on big issues, settling any outstanding policy concerns - such as the financing of the NHS, the future of Trident and nuclear energy, for example - and even bringing a bit of chutzpah to the role.
The new leader has a hard act to follow
It is also important the new leader walks the difficult political tightrope between Labour and the Tories - while pledging no post-election deals with either of them.
Without Iraq as an issue to attract disaffected Labour voters, the new man will need to send out other signals - perhaps on civil liberties - that will still appeal to them.
But, perhaps more importantly, he needs to defend his other flank against a resurgent Conservative Party which is determined to move its tanks firmly onto the centre ground, forcing the third party once again to the fringes.
Specifically, he needs to attract the votes the Lib Dems now need to do well in the next general election - and they are, largely, Tory votes.
At the same time, he will need to stop Lib Dem voters, particularly in the south west, switching to Cameron's 'liberal Conservatives'.
The great goal for the party must be to do enough to stop the Tories winning the next election, leaving them with the balance of power in Westminster.
Finally, the new leader has to match or even out-perform Mr Cable.
There would be an awful irony if the new, young (or young-ish) leader found himself being unfavourably compared to the man who decided not to stand because of ageism.
Who, in those circumstances, could rule out a "bring back Cable" campaign starting to roll?