THE WHITE HOUSE / SHAPING LEGISLATION : Under Bush, Veto Is Potent Tool for Battling Congress : The President has lost a large number of votes on Capitol Hill. But he has been sustained in killing 11 bills.

At the center of President Bush’s record of wins and losses on Capitol Hill there is a puzzling contrast: Bush has won fewer votes in Congress than almost any other President in this century, but on the ultimate test--sustaining vetoes--he has the best record ever.

When the Senate late Tuesday night upheld Bush’s veto of a bill authorizing money for Amtrak, it was Bush’s 11th consecutive victory in a veto fight. He has not been overridden.

As a result, a senior White House aide said, the veto power has become a “crucial strategic tool” for the Administration, one that is central to the legislative strategy developed by Bush and his chief of staff, John H. Sununu.

PREDICTIONS DEFIED: The success has surprised those who predicted, when Bush took office, that Democratic control of the House and Senate--coupled with a campaign that yielded few clear verdicts on policy--would force the Administration to compromise and conciliate to achieve any legislative victories.

Bush has been defeated often in congressional votes. A study by Congressional Quarterly at the conclusion of Bush’s first year in office found that the Administration had been defeated more than one-third of the time on votes on which the White House took a firm position. Only Gerald R. Ford, facing a huge Democratic majority and taking office in the wake of the Watergate scandal, had fared worse.

But, because of the veto power, the losses Bush has suffered seldom have had a major impact on policy. Last year, for example, Congress passed minimum wage legislation that the White House opposed. Bush vetoed it, Congress failed to override the veto, and, in the end, congressional leaders had to settle for a compromise on Bush’s terms.

A NEW APPROACH: Bush’s use of the veto power has been notably different from that of his predecessor, an official who served both administrations said. “The Reagan Administration was famous for saying they’d veto almost everything and actually vetoing almost nothing,” the official said. By contrast, Bush has made relatively few veto threats but, in almost all cases, has followed through on them.

In doing so, Bush often has acted against traditional political wisdom. The Amtrak bill, for example, originally was passed by the House by a margin of 322 to 93 and cleared the Senate on a non-controversial voice vote. Presidents facing that sort of margin seldom venture a veto.

Traditionally, analysts of the presidency have seen the veto as essentially a negative power, a technique that could be used to block action but not something that could be used effectively to shape legislation. Under that analysis, overuse of the veto would be likely to lead to legislative gridlock.

So far, however, Bush has largely proved that analysis wrong. Because Bush has very few legislative initiatives he wants to see passed, he has less to fear from gridlock than congressional Democrats do. And, because he has been able to win every veto fight so far, Democratic leaders increasingly have been willing to negotiate with the White House rather than risk a confrontation they ultimately would stand a good chance of losing.

OPPOSITION CATCHING ON?: Although Bush and his aides so far have been able to outmaneuver the Democrats repeatedly, there are signs that the opposition is beginning to learn from its mistakes. And, in at least one case, civil rights, an Administration veto threat may have backfired.

On civil rights, the Administration, led by Atty. Gen. Dick Thornburgh, issued a veto threat aimed at a bill to overturn several Supreme Court decisions that have made it more difficult for plaintiffs to win discrimination suits. But, earlier this spring, the White House began to back down, worried that vetoing a civil rights bill would damage Bush’s efforts to attract support in the black community.

Now, Sununu and other Administration officials have begun negotiations with key congressional supporters of the bill, particularly Sen. Edward M. Kennedy (D-Mass.). But White House officials admit that the public wavering on the veto threat has put them in a weakened bargaining position.

Supporters of the bill “may just figure the President wouldn’t dare veto it or, if he did, we wouldn’t have the votes to sustain a veto,” one senior Administration official said. “I’m not sure.”