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I think Joe Biden is a smart choice for Barack Obama. With nearly 36 years in Washington and much of it atop the Senate Foreign Relations Committee, the Delaware senator's got decades of knowledge about how the U.S. national-security apparatus works and a clear-eyed, unromantic view of America's role in the world.

This experience has made Biden nothing if not extremely confident in his views, which makes him well suited to play the role of Democratic attack dog on foreign policy.

One of his favorite tactics is ridicule: Everyone remembers him saying that a Rudy Giuliani sentence has only three words: "a noun, a verb, and 9/11" during the primary season. But Biden's a pretty serious guy, too. He believes Democrats, who usually poll below Republicans on national security, shouldn't "play defense on foreign affairs," and he leads by example in his frequent op-eds and appearances on the Sunday talk shows.

Watch him take on President Bush here on Meet the Press:

The big rap on Biden, of course, is that he's gaffe-prone and likes to talk, and that's certainly true. Dana Milbank had some fun with the prolix Delaware senator after his questioning of Bush Supreme Court nominee Samuel A. Alito Jr.:

Sen. Joseph R. Biden Jr. (D-Del.), in his first 12 minutes of questioning the nominee, managed to get off only one question. Instead, during his 30-minute round of questioning, Biden spoke about his own Irish American roots, his "Grandfather Finnegan," his son's application to Princeton (he attended the University of Pennsylvania instead, Biden said), a speech the senator gave on the Princeton campus, the fact that Biden is "not a Princeton fan," and his views on the eyeglasses of Sen. Dianne Feinstein (D-Calif.).

Biden's got a good sense of humor about it, though: Watch him eat humble pie on the Daily Show just after he called Barack Obama "the first mainstream African-American... who is articulate and bright and clean and a nice-looking guy." Asked during one of the Democratic debates if he thought he could control himself as president, he simply said, "Yes."

But as much as he likes to talk, Biden's actually a pretty nuanced foreign-policy thinker. He doesn't have strong ideological views, so he's hard to pigeonhole. Looking over his statements and policies over the years, I'd say he hews to a pragmatic form of liberal internationalism backed by American power. I think he takes his responsibilities very seriously.

He uses the term "national interests" frequently, but he's not quite a Scowcroftian realist -- as his push for action in the Balkans and Sudan demonstrates. Nor is he quite a "liberal hawk," either. He has little patience for sweeping rhetoric about how the United States is bringing freedom and democracy to Iraq, and he doesn't (unlike certain other Democratic senators who were passed over for veep) default to the hawkish position on national security just for the sake of sounding "tough". He believes that some situations call for toughness (Sudan) while others call for engagement (Iran). He understands both the need for and the limits of multilateral institutions, and he doesn't see multilateralism as an end in itself, unlike some in his party.

That said, Biden doesn't bat 100 percent. He went ahead and supported the Iraq war despite warning that President Bush was underestimating the risks (he now says he didn't realize Bush would be so incompetent and that he thought Saddam could be deposed by other means). He called the surge "a tragic mistake" in February 2007 while John McCain has backing it wholeheartedly.

But he has gotten lots of other issues right, in my view: He has been calling for years for more resources in Afghanistan, for a more coherent U.S. relationship with Russia, for engagement with Iran, for a broader U.S. strategy toward Pakistan, and so on.

How much influence will Biden have on Obama's foreign-policy views? We'll have to see. But I imagine it will be considerable. Biden doesn't seem like the kind of guy who will simply stick to the talking points he's handed. Should be fun to watch.