House Democrats looking to override a bevy of threatened vetoes picked up a key ally Tuesday night as a candidate with a familiar name won a special election to fill a vacant seat in Massachusetts.

Niki Tsongas, widow of 1992 presidential candidate Paul Tsongas, could be sworn in as early as Wednesday, which would give her the opportunity to participate in Thursday's vote to override the veto of a measure to add millions of children to a federally funded health insurance program.

Recently, President Bush vetoed legislation to expand the State Children's Health Insurance Program and has pledged to veto a terror surveillance bill set for a vote Wednesday in the House and a recently approved House bill to shield reporters' sources from testifying in federal cases.

Bush's SCHIP veto was a flashpoint for Tsongas, who lambasted Republican opponent Jim Ogonowski for refusing to say before the election how he would vote.

"You can continue the change in direction that was started in the midterm elections or you can send someone to Congress who's basically another vote for George Bush," said Tsongas, a community college dean.

Tsongas, 61, said she would vote for the override.

Ogonowski, 50, a farmer who retired from the Air Force in June after a 28-year career, said he wouldn't declare his position on the SCHIP bill because he wanted to use his first day in Congress to try to negotiate an alternative.

Tsongas edged out Ogonowski, the brother of an American Airlines pilot who died in the Sept. 11 attacks, by capturing 51 percent of the vote to his 46 percent with 86 percent of precincts reporting.

Tsongas fills the northeastern Massachusetts district seat once held by her late husband. The seat was left empty in July when Democrat Martin Meehan resigned to become chancellor of his alma mater, the University of Massachusetts-Lowell.

Tsongas becomes the only woman in the state's 10-member House delegation and the first to represent Massachusetts since 1983, when Republican Margaret Heckler left office.

Tsongas and Ogonowski, whose brother John died when his plane was hijacked and flown into the World Trade Center, cast the race as a referendum on President Bush's policies or a public upbraiding of the Democratically controlled Congress.

Bush and Congress have lagged in recent public opinion polls, and the race may have served as a harbinger of the 2008 presidential campaign. Primaries and caucuses for the White House nominations begin in fewer than three months.

Tsongas' husband died in 1997 of side effects from the cancer that prompted him to retire from the Senate in 1985. He beat fellow Democrat Bill Clinton in the 1992 New Hampshire primary during a period of remission.

Also on the ballot Tuesday were independent candidates Kurt Hayes and Patrick Murphy and Constitution Party candidate Kevin Thompson.