Obama ends the long war

The 2011 deadline for troop withdrawal was set by former US President George W Bush

Obama rose to power, in part, because of his opposition to the war in Iraq.

Now he has promised that it will finally be over by the end of the year.

The date was actually negotiated by the Bush administration in 2008.

But many expected that the deal would be fudged and a substantial number of troops would remain.

It is not a coincidence that election year 2012 will begin with all the troops out of Iraq and a good number of them gone from Afghanistan.

Power with altitude

The reason that all the troops are coming home is that the Iraqis wouldn't promise to give any who remained immunity from prosecution.

This "deal breaker" may have delighted the White House, allowing Friday's unequivocal announcement.

The Pentagon would have liked about 3,000 to stay, including special forces.

The president's short statement in the White House briefing room didn't propose an Obama doctrine.

But the hints were there.

By mentioning the dramatic death of Gaddafi and the operation to kill Bin Laden, he suggested that US power would be used in a different way in the future.

Not putting troops in harm's way, but hard power with altitude. Drones in the air, not boots on the ground.

There's something a little trite about the argument that this is "a new way of war".

It ignores the fact that different sorts of crisis may dictate different responses. But President Obama would move heaven and earth to avoid sending American troops into a foreign country.

There are some in the US who feel uneasy about this, arguing "shrinking America's role in the world is the true Obama doctrine".

Republican hopeful Mitt Romney has tweeted: "@BarackObama's astonishing failure to secure an orderly transition in Iraq has unnecessarily put at risk victories won at great sacrifice."

But a lot of Americans are fed up with war, and talking about it, and are much more worried about getting, or keeping, a job.

Democrats will be delighted by the news.

The president didn't pull his punches, or try to pretend this was a national security issue.

He said: "After a decade of war, the nation that we need to build and the nation that we will build is our own - an America that sees its economic strength restored just as we've restored our leadership around the globe."

In campaigning terms, this autumn is a luxury for Obama.

While Republicans bicker among themselves over the choice of a candidate, he is using the time exciting his own base, or at least demonstrating he's doing what they want.

The Iraq announcement is part of that.