Known as one of the Senate's more moderate Democrats, Mary Landrieu (search) of Louisiana undertook a fiery defense Sunday of military reservists that threatened to delay passage of a corporate tax bill and keep lawmakers in the Capitol rather than out campaigning.

"I'm not going anywhere," Landrieu said.

She noted that she had made arrangements for her two small children and was ready to lead all-night filibusters (search) to stop a vote on a bill offering $136 billion in tax breaks for manufacturers.

Landrieu was incensed that the final version of the bill did not include a tax credit to encourage employers to make up for the pay lost by members of the Reserve (search) and National Guard (search) who are called to active duty.

"I'm going to use all the parliamentary procedures available to me as a senator to fight for the 5,000 men and women in the state of Louisiana who are currently activated," she said. "If I have to stay on the floor for next four days, I intend to do that."

It could take until Thursday to clear the possible procedural obstacles to the tax bill and two spending bills that the Senate wants to complete before recessing for the Nov. 2 election.

Landrieu, 48, notes proudly on her Senate Web page that she has been called "military Mary" because of her dedication to the military services and that she has strongly supported robust defense spending. Louisiana is the home of three major military installations and some of the nation's biggest shipbuilders.

She also has put her state's interests first in backing the oil and gas industries, and was one of a minority of Democrats to support development of Alaska's Arctic National Wildlife Refuge (search).

Staying alert to sentiments back home has been essential for Landrieu. She barely won election to the Senate in 1996 and had to endure a challenge by her Republican opponent that led to a nearly yearlong Senate inquiry.

While a party loyalist on most issues, Landrieu has not been shy about joining Republicans when it has come to reflecting the conservative leanings of her constituents.

She has voted for several of President Bush's tax cuts, a constitutional amendment to balance the budget and the resolution granting Bush authority to go to war in Iraq.

Landrieu is the oldest of nine children of Moon Landrieu (search), who was major of New Orleans in the 1970s and secretary of Housing and Urban Development in the Carter administration.

She was elected to the Louisiana Legislature in 1979 at age 23, the youngest woman to do so.