WASHINGTON — Washington. -- Some newspapers called it a victory for the White House, a defeat for Democrats in the Congress, when the president's veto on the abortion ''gag rule'' was upheld. But it was a costly victory for the president. Even many people opposed to abortion did not want to see the First Amendment violated by a federal regulation, one telling a doctor what he or she can say to a patient.
The president might profitably have waffled on this, but for one thing: We are already seeing the results of the threat that has arisen on his right. He would give Pat Buchanan ammunition if he backed off from his pledge to oppose abortion. It is the hard core of his own support that he must look to now.
Most presidents have the luxury of counting on a firm base of their party's loyalists while they maneuver out toward other constituencies. But this flexibility is considerably impaired if that partisan base becomes wobbly. That is when presidents have reacted energetically, almost with panic.
Franklin Roosevelt is said to have feared a Huey Long candidacy in 1936, one that would have called for more radical action than Roosevelt was willing to endorse. President Carter went after a challenge from Edward Kennedy with a kind of pious ferocity in 1980.
Pat Buchanan, expected to enter the New Hampshire primary, knows very well the menace of a revolt among regulars. He was in Nixon's White House in 1972, where he helped contain an insurgency by Republican congressman John Ashbrook. Mr. Buchanan and Spiro Agnew were deputed to keep the right wing from forming ranks behind Mr. Ashbrook, who was voicing concerns over Mr. Nixon's wage and price controls and his accommodation of ''Red China.''
One result of that effort was that Mr. Nixon had to give up his hope of substituting John Connally for Spiro Agnew. Mr. Agnew had done valuable service in opposing Mr. Ashbrook's bid.
David Duke presents a different kind of threat, but one that could be even more important. If he enters the race, he will be like George Wallace, the man who was squeezed out of the Democratic Party in 1968 but went on to win 14 percent of the general vote. In the spring of 1968 he was winning almost a third of the national vote in some polls, appealing to the same kinds of discontent with minorities, supposedly coddled by government, that Mr. Duke has tapped into now.
Some have called Mr. Duke the outgrowth of the Willie Horton appeal in 1988, a growth Mr. Bush himself planted and watered in his last campaign. But he is the continuation of something more basic. Spiro Agnew had to appeal to Wallace's voters during Mr. Nixon's first term -- using strident rhetoric written for him by Pat Buchanan (that name again). After the attempt on Wallace's life in 1972, his vote was absorbed into the Nixon landslide of that year, hurrying the switch of Southern Democrats to the Republican Party.
This was the new coalition Ronald Reagan appealed to and based his electoral victories on. It had a basically Wallace-type component all along. Mr. Duke is now trying to break off that part of the Republican structure, to use it for his own purposes. No wonder he has the White House worried. Richard Nixon won by a plurality in his close 1968 race, because people even more right-wing than he were going to Wallace. President Bush, with all his other troubles, cannot afford to let something analogous happen in 1992. But it might.
6* Garry Wills is a syndicated columnist.