Joe Biden’s biggest asset is said to be his expertise on foreign policy. But he showed an amazing lack of commonsense during his 2002 vote authorizing war against Iraq.

What was Biden thinking? Either he isn’t as smart as people believe he is, or he was completely bending to the prevailing political winds. I would suspect it was more of the latter.

Matthew Yglesias at the Center for American Progress Action Fund gives an interesting rundown on Biden’s pre-war performance that shows Biden engaging in all sorts of contortions. Biden pointed out several flaws in the Bush Administration’s push to war in speeches he made in that time period. And, yet, he voted to let them off the leash!

“Biden seems to believe, in a massive misunderstanding of how things work, that by signing on with the Administration he would be able to weigh in on the side of the non-crazy faction and thus influence events in a positive manner,” Yglesias writes. “I don’t really understand why he would have thought that would work.”

In a recent open letter, former CIA analyst Ray McGovern caustically told Biden, “There is no getting away from the important role you played in roping Congress into facilitating that war.”

McGovern reminds us of how Scott Ritter, the former U.N. weapons inspector, called the Biden-chaired pre-war hearings a “sham … to provide political cover for a massive military attack on Iraq.”

In the years since, Biden has pretended that everyone thought that Saddam had WMDs and that the authorization of force was not quite a green signal for Bush to attack Iraq. Sorry. Even someone with my limited expertise knew back then that both of these propositions were false.

Biden has in the recent past tried to make amends by being critical of the war and has even called for a repeal of the 2002 war authorization. Too late for a mulligan. (And, curiously, Biden has latched on to another weird notion: that Iraq needs to be federated—read divided—into three states.)

For the rest, Biden’s foreign policy record has been mixed over his thirty-five long years in office. (And here I’m indebted to Professor Stephen Zunes’s incisive analysis for Foreign Policy in Focus.)

Recently, he’s been good on Iran (calling for negotiations and voting against the bill deeming the Iranian Revolutionary Guards a terrorist organization) but belligerent toward Russia during the Georgia conflict. Further back, he was good on the Nicaragua Contras but bad on key free trade agreements such as NAFTA. And, as Zunes points out, he has been quite horrible on the Israel/Palestine issue.

But it’s the Iraq War vote that he’ll have to live down for the rest of his days. All his much-vaunted expertise didn’t serve him too well on the key foreign policy issue of our era.