In deciding to use an open primary to select the Tory Rochester by-election candidate, the Conservative leader has helped to set the stakes extraordinarily high.
Nick Clegg revealed that George Osborne, when he refused to implement a bigger tax threshold leap in the 2012 budget, said: "I don't want to deliver a Lib Dem budget."
Danny Alexander is not without ambition. Over time he has tried various tactics to convince Lib Dems that they should take him to their hearts and consider him future leadership material.
The PM told security chiefs at Chequers he wanted to be sure everything possible was being done to track down the killers of Alan Henning. But is there enough intelligence to find them?
Thousands poured into the area around the Lib Dem Conference in Glasgow at lunchtime, just as the debates were getting under way. Alas for the Lib Dems they were here to see live comedy next door...
Ex-president of the European Court of Human Rights Sir Nicolas Bratza says Tory plans to ignore European rulings would put the UK parliament in breach of international law and "set a bad example".
In a politically disengaged era the PM aims to catch voters' attention with some direct cash offers on taxation and some direct political messages too.
Theresa May and Boris Johnson have a small cadre of parliamentary acolytes who hope their candidate will succeed David Cameron.
Senior Tories say they've road-tested today's announcement to death. There is strong voter support; it has gone down "extremely well" in the focus groups.
George Osborne sticks rigidly to the line that the Tory leadership is not shifting its position on whether there are any circumstances in which it might back an "out" vote in an "in/out" referendum.
They're waving union jacks in the hall of the Tory Party Conference in Birmingham but in a hectic high-octane three weeks of politics this flag was nearly ditched.
One minister said the truth is that the attacks that will be authorised with today's vote are one step on a ladder of 20 rungs and no one really knows what the other steps will turn out to be.
Seeking parliamentary approval before military action has brought in a new era that inhibits prime ministers in a way that would be unthinkable to their predecessors.
The idea behind Ed Miliband's speech was to make the forthcoming election a battle of the plans, and its central message was solidarity - or "the spirit of together".
Parliament could be recalled as soon as Friday for a vote on military action against Isil in their Iraqi and Syrian bases. The government is increasingly confident it has Labour on board.