From her first trip to Washington more than three decades ago, one memory stands out.

For nearly two hours, Susan Collins, then a senior at Caribou High School, sat across from Margaret Chase Smith in the senator's Capitol office and talked about national defense, full employment and other weighty issues of the day.

In retrospect, the specifics matter little. What matters is the impression Smith made on this girl, winner of the trip to Washington in a national competition.

"I remember leaving her office and thinking that if she can be in the Senate, women can do anything," Collins said.

Smith was a lioness of the Senate - a Republican woman from Maine who was willing to break with her party. All these years later, Susan Collins is just that. And so is Olympia Snowe.

Snowe and Collins, after ascending to the Senate in the mid-1990s, are influential centrists in an increasingly polarized body. Like Smith, who served 24 years in the Senate, they are moderate Republican women with an independent streak who are leaving their mark on an institution in which fewer than 35 women have ever served.

When the GOP majority was poised to eliminate the filibuster on judicial nominations - an initiative so fearsome it was dubbed the "nuclear option" - Snowe and Collins were among 14 senators who forged the compromise that forestalled devastation.

When President Bush and Republican leaders pressed for cuts in Medicaid spending, Snowe and Collins were among seven Republicans who joined the Democrats in rejecting the proposal. Snowe has opposed Bush's proposed personal accounts to augment Social Security; Collins has said she has not made up her mind.

Norman Ornstein of the American Enterprise Institute, who worked with Snowe on campaign finance reform, said she has "a remarkable inner strength," while "Collins also has a strong streak of independence, but a slightly greater inclination to go with the party when she can."

"But both are deeply prized in Washington for their intelligence, decency, legislative savvy and willingness to be bipartisan in an era where the conflict has become almost tribal and primal," Ornstein said.

They are both pro-choice, breaking with the GOP on the emotional vote over so-called "partial birth" abortion, and have shunned opposition to gay rights. As deficit hawks, they helped stave off the Bush administration's deepest tax cuts. And after President Clinton was impeached by the House of Representatives, they angered Republican partisans by voting against removing him from office.

Margaret Chase Smith's life story also touched a chord with Snowe, who experienced tragedy at an early age. The daughter of Greek immigrants, she was orphaned at age 9. And she was widowed at 26 when her husband was killed in a car crash on the Maine Turnpike while returning home from a session of the Maine House of Representatives.

Following Smith's path, she ran for the Legislature in her husband's district and won. She has never lost an election.

Collins, 52, had worked as an aide to William Cohen, former Maine senator and secretary of defense, and as a state and federal administrator before losing a bid for governor in 1994. She came back to win her Senate seat two years later.

Both are viewed as hard workers, return to Maine virtually every weekend, have talented staffs and provide solid constituent services.

And both, at times, have been marginalized by their own party because of their middle-of-the-road stance. Their departure from GOP orthodoxy on economic, environmental and most of all social issues has put them in the crosshairs of conservatives who deride them as RINOs - Republicans in name only.

"My vision of what the Republican Party should stand for is not what Susan and Olympia feel it should stand for," said Scott Fish, an activist and founder of www.asmainegoes.com, a clearinghouse for conservatives.

But here in Maine, they like what the two senators stand for. An independent statewide poll last month showed Snowe and Collins with approval ratings of 65 percent and 58 percent, respectively, compared with 31 percent for President Bush and 29 percent for Democratic Gov. John Baldacci.

And despite their willingness to break Republican ranks, Snowe and Collins maintain a friendly relationship with Bush, having known him from their visits to his father's summer home in Kennebunkport.

They are, after all, moderates, and are not given to intemperate behavior. They do not see themselves as renegades because they broke with the leadership on judicial filibusters.

"We know moderates can continue to play a pivotal role on a lot of issues, but we don't want to be a substitute for leadership," Snowe said. "We organized simply on this particular issue, but it demonstrates that it could be done."