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.

Lee said the four lawmakers began to reach out to each other in early 2011. “Little by little, those of us who share a lot of these beliefs in common found each other as people who saw the issues in a similar way,” he explained, adding, “We definitely have each other’s cell phone numbers.” Around that time, Lee and Paul were two of the only three Republicans to vote against reauthorizing the Patriot Act, while Wyden used the reauthorization to launch an (unsuccessful) effort to force the Obama administration to disclose what he said was a classified interpretation of the law.

Wyden and Paul are the central pairing in the group—and in terms of U.S. politics, the two lawmakers are chalk and cheese. It’s true that Wyden has proven willing to cross party lines on issues like Medicare reform, but the Oregon senator has generally been a reliable defender of liberal government programs. Paul, on the other hand, has developed a cantankerous reputation as an uncompromising leader of the Tea Party. (To take just one example: in July, he said that doctors under Obamacare would collect information for a government database on which citizens owned guns.)

Yet despite these political differences, the two recently told The Daily Beast in separate interviews that they like each other. “I have a great deal of respect for him. I point to people like Wyden and say, ‘If he wanted to accept the progressive label, it would be a proud label,’” Paul said. “Most of these liberal Democrats, they are more right wing than the neocons.” Wyden returned the compliment, saying of Paul: “He is very straightforward with me. For me, that is the coin of the realm. Everyone in the Senate has strong views and different positions. The single most important thing in politics and government: when someone says, ‘I will do point A,’ that he means it.”

The two lawmakers do not socialize. Paul says this is because he likes to spend his weekends in his home state of Kentucky. Nonetheless, the two have formed an office friendship, instructing their staffs to work together at times—and not only on national security issues. Last year, for example, Paul co-sponsored a bill drafted by Wyden to allow farmers to grow industrial hemp.

Prior to a few weeks ago, the alliance had not enjoyed much policy success. Yet now, on the question of drones—specifically their demand that the Obama administration release more details on the drone program before Brennan’s nomination is allowed to proceed through the Senate Intelligence Committee—they seem to have found an issue with legs. “I feel very strongly that the intelligence committee has to have any and all legal opinions related to targeted killings before there is a committee vote,” Wyden said. “Only about once every two years does the Congress have the maximum ability to do the kind of vigorous oversight that is necessary.”

The ACLU, not surprisingly, approves of the alliance. “A bipartisan group of senators in 2004 and 2005 were right to ask for and demand the legal opinions undergirding the torture programs,” says Chris Anders, a senior legislative counsel for the Washington office of the ACLU. “In 2013, a bipartisan group of senators is right to demand the legal opinions undergirding the killing program.”

Interestingly, Wyden and Paul are not the only ones who find themselves with strange bedfellows these days. John Yoo, the extremely conservative Justice Department lawyer who during the Bush administration wrote the legal opinions authorizing waterboarding and other harsh interrogation techniques for the CIA, told The Daily Beast that the senators were mainly posturing in their demands for the legal memos. “The idea that senators are going to pretend they don’t know about any of this is very interesting,” Yoo said. “They are fully briefed by the CIA when they are occurring.” In saying this, the former Bush official was effectively allying himself with the Obama administration position. Drones, it turns out, have a way of creating odd ideological pairings—on both sides.