If you’ve followed the drawn-out saga surrounding John Brennan’s nomination to be CIA director—with all the questions it has raised about drones and targeting of American citizens—you may have noticed something odd: one of the Senate’s longtime liberals, Ron Wyden of Oregon, has appeared to be very much on the same page as Rand Paul of Kentucky, arguably the most ardent Tea Partier on Capitol Hill.

It turns out this isn’t just a fleeting alliance. For some time now, Wyden and Paul—along with two other senators, Republican Mike Lee of Utah and Democrat Mark Udall of Colorado—have been working together to try to curb the broad authorities the Obama administration has asserted in the war on terror. The advent of this group, which calls itself the Checks and Balances Caucus, is certainly not the first time in political history that the libertarian right has allied with the civil-liberties-minded left. Yet at a moment when inter-party cooperation is almost nonexistent in Washington, any bipartisan alliance—especially one that includes some of DC’s most committed ideological opposites—is both unusual and noteworthy.