The possible entry of syndicated columnist Patrick Buchanan into the presidential primary process already is enlivening what otherwise would have been a stuffy, mechanical and automatic renomination of the Bush-Quayle ticket.

But Buchanan’s flirtation with a challenge to an incumbent Republican president — while it is good news for a strong democratic process — could be bad news for the GOP. It signals serious, perhaps fatal internal political weakness.

Pulled by a public that is solidly in the mainstream on most issues, threatened with an election-year recession and a brewing rebellion against entrenched special interests, incumbency and even wealth, President George Bush has abandoned his roots in the conservative wing of his party. The result is a president without a philosophical compass.

Last week’s disorientation exercise produced a bizarre scenario in which the president was taking pen to the new civil rights act (which is anathema to GOP conservatives), while his chief of staff was following the president’s historic instincts (Mr. Bush voted against the last civil rights act, in 1964), and was preparing a memo on White House personnel practices that repudiated many of the important features of the bill being signed by the boss.

President Bush is slipping. His supporters no longer know what he stands for, and as a new-look moderate he will not convince undecided voters — he comes across as vacillating and insincere.

If he runs, Mr. Buchanan is not likely to win, but given his aggressive temperament and his no-quarter approach to political debate, he is very likely to force Mr. Bush to put form to his 1992-model-year presidential philosophy, just in time for the main event with the Democratic challenger.