ONE lesson of George Bush's unbroken streak of 24 sustained vetoes: He picks his fights with great finesse.Just hours before the US House of Representatives attempted to override the veto on abortion counseling in federally funded clinics last week, Speaker Thomas Foley (D) of Washington was still optimistic about an override. But White House aides were already calling the vote on the nose: The override would fall 12 votes short of the necessary two-thirds of the House. This kind of keen political scout work by the White House is credited with much of the president's success in eking maximum leverage out of a divided government - even in troubled times. Mr. Bush has yet to make a veto promise he can't keep or a veto he can't sustain. "The White House has very good intelligence and very good liaison on which issues they should veto and when they can sustain a veto," says Georgetown University Prof. Stephen Wayne. In spite of the president's current trouble in communicating assurance to the public, Dave Mason of the conservative Heritage Foundation notes that "he has a very good political sense for inside Washington." The simple explanation for why Bush has been so successful in sustaining his vetoes lies in the numbers. He faces 268 Democrats in a House that requires 291 votes to override a veto. In the Senate, Democrats hold 56 seats but need 67 votes to override. But other Republican presidents have faced similar or weaker opposition in Congress and still suffered overrides. Presidents Gerald Ford, Richard Nixon, and Ronald Reagan each were overridden on about 25 percent of their vetoes. Popularity is a factor as well. President Bush is now measuring about 55 to 56 percent job approval in the polls - down roughly 10 points in recent weeks. But over time his popularity is unequaled by other presidents in the history of polling. Only Eisenhower and Kennedy come close. Most observers see a strong pull on Republican congressmen not to embarrass their president and party leader by overriding his veto. "Certainly up to now, there has been a strong fear of voting to override the president," says Mr. Mason. But in the current climate, he adds, "it's fading fast." Mr. Nixon suffered few overrides until after the Watergate scandal, when his support began ebbing. The War Powers Act - still a difficult law for conservative presidents to accept - was passed over his veto after Watergate. Veto votes do not always follow party lines, certainly. Last week's veto was of the annual appropriation for the Department of Health and Human Services. The White House claimed strong objections to as many as 10 elements of the bill. But the veto message singled out one - Congress's attempt to cancel regulations that bar clinics receiving federal funds from discussing abortion with patients. A broader veto message with a long list of objections might have rallied Congress into a battle over the power of the two branches. Singling out the abortion-counseling issue forced a focus where the White House could form a coalition to block the override. Bush has been very clear from early in the drafting of legislation about what he would veto and why. He always follows through. When Mason worked in the Republican whip's office during the Reagan administration, he recalls, "Ronald Reagan would threaten to veto everything that came down the pike." He often failed to follow through, however, making it difficult for even his supporters to tell when he was serious. The veto is a tool that suits the Bush agenda, since it is better at paring down bills and forcing items out of them than expanding or forcing new items in. "A veto is a good weapon to say 'give me less, says political scientist George Edwards of Texas A&M. "You cannot use a veto to get an innovation," he says, such as a capital-gains tax cut or aid for the Soviets.