SAYING WHAT FEW LAWMAKERS WILL…. Rep. Alan Grayson (D-Fla.) appeared on MSNBC’s “Hardball” last night, and Chris Matthews asked the freshman lawmaker to comment on Dick Cheney’s suggestion that President Obama might be guilty of giving “aid and comfort” to the enemy.

“You know, on the Internet there’s an acronym that’s used to apply to situations like this,” Grayson said. “It’s called ‘STFU.’ I don’t think I can say that on the air, but I think you know what that means.”

Matthews asked for a hint, before figuring it out and urging Grayson to avoid “crude language.” (If you find it hard to believe that Chris Matthews has never come across “STFU,” then we’re on the same page.)

Whether lawmakers should make remarks like these is open to debate, but Grayson’s on-air comments are a reminder that we’re just not accustomed to liberal Democrats playing by these rules. It’s jarring because it’s so unusual.

Matt Yglesias recently argued that Grayson is “breaking one of the unspoken rules of modern American politics. The rule is that conservatives talk about their causes in stark, moralistic terms and progressives don’t. Instead, progressives talk about our causes in bloodless technocratic terms…. [M]oralism from the left is very unfamiliar to American political debates.”

I suppose everyone has different expectations and preferences when it comes to the standards of the political discourse. But Rep. Barney Frank’s (D-Mass.) recent assessment of Grayson sounded about right: “I welcome Grayson’s taking the fight to them. I think he has got to be a little more careful about his punches, but I am glad he’s throwing them.”

There’s room on the rhetorical spectrum from staid, clinical wonkery to unapologetic firebrands. Grayson, love him or hate him, is filling a niche.

Steve Benen

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.