But back to the main theme. What has been really striking has been the eliminationist rhetoric of the G.O.P., coming not from some radical fringe but from the party’s leaders. John Boehner, the House minority leader, declared that the passage of health reform was “Armageddon.” The Republican National Committee put out a fund-raising appeal that included a picture of Nancy Pelosi, the speaker of the House, surrounded by flames, while the committee’s chairman declared that it was time to put Ms. Pelosi on “the firing line.” And Sarah Palin put out a map literally putting Democratic lawmakers in the cross hairs of a rifle sight.

Image Paul Krugman Credit... Fred R. Conrad/The New York Times

All of this goes far beyond politics as usual. Democrats had a lot of harsh things to say about former President George W. Bush  but you’ll search in vain for anything comparably menacing, anything that even hinted at an appeal to violence, from members of Congress, let alone senior party officials.

No, to find anything like what we’re seeing now you have to go back to the last time a Democrat was president. Like President Obama, Bill Clinton faced a G.O.P. that denied his legitimacy  Dick Armey, the second-ranking House Republican (and now a Tea Party leader) referred to him as “your president.” Threats were common: President Clinton, declared Senator Jesse Helms of North Carolina, “better watch out if he comes down here. He’d better have a bodyguard.” (Helms later expressed regrets over the remark  but only after a media firestorm.) And once they controlled Congress, Republicans tried to govern as if they held the White House, too, eventually shutting down the federal government in an attempt to bully Mr. Clinton into submission.

Mr. Obama seems to have sincerely believed that he would face a different reception. And he made a real try at bipartisanship, nearly losing his chance at health reform by frittering away months in a vain attempt to get a few Republicans on board. At this point, however, it’s clear that any Democratic president will face total opposition from a Republican Party that is completely dominated by right-wing extremists.

For today’s G.O.P. is, fully and finally, the party of Ronald Reagan  not Reagan the pragmatic politician, who could and did strike deals with Democrats, but Reagan the antigovernment fanatic, who warned that Medicare would destroy American freedom. It’s a party that sees modest efforts to improve Americans’ economic and health security not merely as unwise, but as monstrous. It’s a party in which paranoid fantasies about the other side  Obama is a socialist, Democrats have totalitarian ambitions  are mainstream. And, as a result, it’s a party that fundamentally doesn’t accept anyone else’s right to govern.