Together, they make up 100 years of collective congressional service, but the departure of Sens. Phil Gramm, R-Texas, Strom Thurmond, R-S.C., and Jesse Helms, R-N.C., symbolizes an end to more than just time spent in Washington.

For some, it signals an end of an era in the U.S. Senate.

Observers say the three men retiring from the Senate this year all represent an ideological wing of the party that never sways from conviction. All three were converts who started out their early careers as Democrats and switched in order to find safe haven for their cultural and fiscal conservatism.

"I think often that converts make for more zealous advocates; it’s certainly true in religion," said conservative activist Paul Weyrich, who added he laments the loss of such staunch keepers of the flame.

"They weren't that important as Democrats, but they certainly were important to Republicans," Weyrich said. "They stood for things, they defended them. It is a generational shift and it does leave a void."

Mike Franc, a government analyst for the Heritage Foundation, agreed.

"The contrast today is younger members from the southern districts [who] have come of age in the Reagan years, it's a different type of Republican," Franc said, calling the elders part of "the pioneer generation," that helped to shape the party in the last 40 years.

But analyst Jim Pinkerton was quick to point out that Helms, 81, and Thurmond, 99, are much older than Gramm, 60, and truly represent "the last real gasp of the neo-Confederate wing of the Republican Party."

Helms and Thurmond are "the white ex-Democrats who debuted in their positions on overtly anti-black platforms," said Pinkerton, a Newsday columnist and regular on Fox News Watch. "To be sure, they mellowed over the years, but it is equally unmistakable that it was the heart of their message and the heart of their careers."

Before his election to the Senate, Thurmond ran for president in 1948 as a Dixiecrat, a Southern splinter group of the Democrats who supported states' rights and opposed the growing civil rights platform in the party. In 1957, he was responsible for the longest filibuster in Senate history, speaking for 24 hours against the Supreme Court desegregation ruling that allowed black children to attend white schools. Later, he became the first senator to hire a black staffer.

"They were certainly deep in the resistance of civil rights," said Ferrel Guillory, director of the Program in Southern Politics, Media and Public Life for the University of North Carolina Chapel Hill. He said it is the presence of these types of conservatives -- who resisted federal intervention even in civil rights matters -- that have turned off potential black voters for years.

"Their departure from the scene might open up opportunities for black voters," he said.

Helms' three decades in the Senate are marked by his work on the Senate Foreign Relations Committee. He used that position to oppose communism, berate the United Nations, and in the 1990s, re-organize the State Department.

Helms was also notorious for holding up President Clinton's Democratic nominations, much the way Democrats are accused of stalling confirmation of President Bush's judicial nominees. Critics argued he prevented the appointment of two North Carolina judges to the Fourth Circuit Court of Appeals because they were black.

Like Thurmond, Helms never swayed from his roots, mostly entrenched in social conservatism. He is pro-life and anti-affirmative action. He admitted earlier this year that as head of the Foreign Relations Committee he did not do enough to stop the spread of HIV in Africa.

Gramm is a different story. An elected Democrat to the House of Representatives in 1978, his support of President Reagan's tax cuts in the early 1980s led to his alienation by the party. He resigned in 1983 and was re-elected as the first Republican in the history of Texas' 6th District the same year.

He was elected senator a year later and has been a champion of free markets and fiscal discipline ever since.

"Gramm was basically as close as you can get to a Libertarian in the U.S. Senate," said Pinkerton.

"So, what you have here is the first generation of party switchers and pioneers of Southern Republicans," said Franc. "All three, in different ways."

What did bind the old guard are their steadfast beliefs. Though Minority Leader Trent Lott, R-Miss., Sens. James Inhofe, R-Okla., Kay Bailey Hutchison, R-Texas, and Don Nickles, R-Okla., can suitably hold down the conservative fort, observers say, their different priorities and willingness to bend on some policy issues make them a different breed of conservative.

"I think [the departing senators'] courageousness, their dedication to principles -- that’s going to be what the current generation of senators will have to step in and fill," said Franc. "It is a vacuum of intensity and a vacuum left by principle-driven legislating they engaged in for so many collective years."