Where’s that toxic rhetoric coming from? Let’s not make a false pretense of balance: it’s coming, overwhelmingly, from the right. It’s hard to imagine a Democratic member of Congress urging constituents to be “armed and dangerous” without being ostracized; but Representative Michele Bachmann, who did just that, is a rising star in the G.O.P.

And there’s a huge contrast in the media. Listen to Rachel Maddow or Keith Olbermann, and you’ll hear a lot of caustic remarks and mockery aimed at Republicans. But you won’t hear jokes about shooting government officials or beheading a journalist at The Washington Post. Listen to Glenn Beck or Bill O’Reilly, and you will.

Of course, the likes of Mr. Beck and Mr. O’Reilly are responding to popular demand. Citizens of other democracies may marvel at the American psyche, at the way efforts by mildly liberal presidents to expand health coverage are met with cries of tyranny and talk of armed resistance. Still, that’s what happens whenever a Democrat occupies the White House, and there’s a market for anyone willing to stoke that anger.