PASSING A TEST OF THE PRESIDENT’S METTLE…. As expected, the Senate approved New START this afternoon by a wide margin. With the process coming to an end, it’s worth pausing to appreciate the larger context, and the extent to which far-right Republicans screwed this up.

By any reasonable measure, this is a major victory for President Obama, who made little secret of the fact he considered the treaty his top priority for the lame-duck session.

But let’s not forget that Republican opponents of New START, following an incoherent strategy, ended up making this an even bigger win for Obama than it otherwise would have been. Adam Serwer had a great item on this yesterday, which rings true.

Early in the Obama administration, Senate Republicans settled on a strategy of total procedural obstruction…. The problem is, the New START treaty is about as controversial as a tuna salad sandwich. Not only has the current military leadership and every living Republican Secretary of State endorsed it, but former Republican national security stalwarts such as Brent Scowcroft are “baffled” by the GOP’s decision to obstruct ratification. New START is also popular — a CNN poll from November shows three quarters of Americans support ratifying the treaty.

If New START is ratified, the only reason it’ll be considered an Obama victory is because Republicans decided to oppose it without any real reason for doing so. If the Senate had simply ratified the treaty without any fuss, Obama might have gotten a few days of positive press, but it wouldn’t have been treated as a major political success. Because Senate Republicans turned ratification into a huge partisan brawl, a Democratic president renewing an agreement with Russia designed by Republican presidents now looks like a massive victory for the administration.

Exactly. New START, which could have very well been negotiated by Reagan himself, builds on the kind of counter-proliferation policy that’s enjoyed broad international support for a generation. Had Republicans treated this the way previous Senates had — which is to say, ratified it fairly quickly with overwhelming support — the political world have barely have blinked an eye.

But Republicans instead decided to turn this into a defining presidential test, and a challenge to Obama’s mettle as a world leader. Left with no choice, Obama fought back as hard as he could, rallying support from the Pentagon and Joint Chiefs, foreign leaders from around the globe, eight former secretaries of state from both parties, five former secretaries of defense from both parties, seven former Strategic Command chiefs, national security advisers from both parties, nearly all former commanders of U.S. nuclear forces — even a former Republican president (H.W. Bush). The president put the full weight of his administration behind this, to ensure success.

And it worked. The result is a victory for the White House that’s even more significant than if the GOP hadn’t needlessly picked a misguided fight.

As Fred Kaplan noted yesterday, “[T]he Republican leadership made this a purely political battle and — fresh off what had seemed a triumphant election season — suffered an astonishingly egregious defeat.”

There’s no denying how significant Republican gains were in the midterms, and the leverage the GOP will try to exploit in the next Congress. But it’s President Obama who’s ending 2010 on a winning streak, looking stronger than at any point in quite a while.

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Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.