WASHINGTON

Usually, at this stage of a presidential campaign, Republicans are doing a much better job of sullying the Democratic candidate as un-American.

Michael Dukakis was accused of having a funny last name and failing to say the Pledge of Allegiance 10 times a day. John Kerry was faulted for acting French and eating Philly cheese steaks with Swiss cheese. Al Gore was into the earth and earth tones — need we say more?

And the G.O.P. has had so much practice over the last four years at skewering Barack Obama as an existentialist socialist apologist for America with a secret foreign birth certificate that it should be like shooting mahi-mahi in a barrel.

The dude used to wear a sarong to do The Sunday Times crossword puzzle, for Pete’s sake — a look more exotic than Ralph Lauren’s Chinese French berets. Yet this week’s Republican attacks have been so shriekingly shrill, they make Poppy Bush campaigning at a New Jersey flag factory back in 1988 look like a masterpiece of subtlety.