So David Cameron has to retrieve airport expansion from the long grass into which he kicked it all those years ago. And the decision's no easier now than it was then. Politically this is a horrible nettle to grasp. If you accept airport expansion is needed - and the Lib Dems and the Greens certainly don't - it has to go somewhere.
And this is the classic example of not being able to please all of the people all of the time. Politically the easier option is Gatwick. Of course it would enrage a handful of Tory MPs in Sussex, Surrey and Kent. But Mr Cameron might think that's a price worth paying. Those are almost all extremely safe Tory seats and are unlikely ever to be lost.
The political opposition to Heathrow is much more significant. There are marginal seats. There are anti-Heathrow cabinet ministers. There is Zac Goldsmith who wants to be an anti-Heathrow Mayor of London. And of course there is Boris. The man-who-would-be-PM's first pledge as the new MP for Uxbridge was to lie down in front of the bulldozers to stop Heathrow expansion.
The Tories themselves pledged no Heathrow expansion in their 2010 manifesto. Their 2015 manifesto talked about responding to the Davies Commission's recommendations. Davies gives the government a convenient excuse - "It wasn't our decision, it's what Davies said".
But it also presents a problem. If politically Mr Cameron thinks Gatwick the easier option, that would be almost impossible if Davies rules it out.It's a decision which will affect all our lives - but especially those who live near airports and those who rely on them for their jobs. When the government finally decide - probably in the autumn - they will be hoping it's early enough in this Parliament not to have much of an effect on the 2020 election.And a decision there will have to be. This can't be kicked into the long grass again.