I don't really want to write this, because I would rather it wasn't true, but I'm not sure how long the euphoria over Barack Obama's jaw-dropping victory can last this side of the pond. I was really struck last week talking to people in and around both Downing Street and David Cameron's shadow cabinet that while there was huge enthusiasm for an Obama presidency, neither thought it would be plain sailing for the UK.
Nobody wants to burst any bubbles, or to pretend this isn't a moment where America changed and the world changed and we hope it's for the better. Most at Westminster think Obama genuinely intends to rebuild those relationships abroad, including the special relationship, so badly damaged by Bush.
But Obama's still going to be US president during a potentially savage recession, at a time of intense pressure to put American interests and American jobs first.
Liam Fox, the shadow defence secretary who usually has his ear close to the ground in Washington, told me nobody should forget that "America will still be America" the morning after Obama wins: it will still sometimes use its power to promote its own interests in ways that may not suit the rest of us.
Downing Street is nervous about what that might mean for America's critical role in overseas aid, when the pressure will be to spend the money at home not abroad - or trade, when the pressure will be to protect American companies and American jobs - as well as foreign policy.
Gordon Brown's challenge is to get Obama locked into a positive international agenda before those domestic pressures can get to him: he'll be hoping to start that process today, when Obama starts talking to leaders around the world (and we find out where the UK is in his pecking order, depending on how long Brown's waiting by the phone....)
It's not a day for raining on parades. But when a once-in-a-lifetime political phenomenon like Obama comes along, there's a tendency to feel that he belongs to all of us: and the truth is he belongs to America first. It's time to find out exactly what that means.
