With bipartisanship being the political order of the day, this is a good time to identify foreign policy issues that are ripe for bipartisanship. Luckily, Vice President Biden is highlighting a tailor-made issue in a policy address at National Defense University today: ratification of the Comprehensive Test Ban Treaty.

The CTBT meshes perfectly with the goal of preventing the spread of nuclear weapons to more countries. The United States and the other established nuclear powers don't need to set off more underground nuclear explosions and have observed a unilateral moratorium for many years -- in our case dating back to the first President Bush. Recent experience with North Korea and Pakistan, on the other hand, reminds us that nuclear tests serve to announce a country's arrival as a nuclear-armed power. (I like to call them a 'lagging indicator' of nuclear proliferation.) So while we shouldn't expect North Korea to sign the CTBT any time soon, the United States has every reason to solidify a treaty saying that test nuclear explosions are a bad thing.

Yet, modern bipartisanship, unfortunately, is a game with moving goalposts. It's like the domestic political equivalent of the neoconservative approach to international negotiations -- instead of give and take, conservatives want all take and no give. As a result, the center of gravity for compromise has moved steadily rightward. When it comes to arms control, Ronald Reagan's policies look so moderate on the contemporary political spectrum that they would certainly come under scathing criticism from today's right wing.

What worries me the most is that there has probably been a rightward shift even in the last couple years, with 2007-08 maybe having been a high water mark of bipartisan comity between moderates. Take for example this May 2008 policy address by presidential candidate John McCain, which voices his explicit openness to CTBT ratification. I sincerely hope Senator McCain still believes these things he said back then, but my reading of the political climate is less optimistic.

One thing that hasn't changed, and leaves me somewhat optimistic, is the reliable moderateness of the old-line Republican establishment. I have to assume that the administration's strategy for CTBT ratification includes the deployment of the lions of the Republican foreign policy community. Watching them vie against contemporary far-right ideology should be fascinating.