Treasury Secretary Tim Geithner tried to portray Republicans as obstructionist during a round of the Sunday talk shows, but he admitted that they have already made their biggest departure from party orthodoxy about taxes in 20 years.

“[Y]ou’ve heard them for the first time, I think, in two decades, acknowledge that they are willing to have revenues go up as part of a balanced plan — that’s a good first step but they have to tell us what they are willing to do on rates and revenues,” Geithner said on Fox News Sunday. “That’s going to very hard for Republicans. We understand that, but there’s no way through this without that.”

Geithner then described his call for a $1.6 trillion tax hike as “a modest increase” that Republicans ought to ratify. “We proposed these things last fall and in the president’s budget, they are very detailed,” he said.