This year’s Senate GOP freshman class is a lonely caucus of one, but the seven GOP Senators elected in 2004 quickly are becoming a force to be reckoned with as Republicans adjust to their new minority status in the chamber.

In the two major legislative debates the Senate has held this year, Democrats found that there would be no honeymoon for their new majority, as several up-and-coming Republicans have introduced amendments that have at times bedeviled the opposition.

“These guys are trying to throw all these things out there and hoping something will stick,” noted one knowledgeable Senate Democratic aide. “We just have to be really careful and watch out for it.”

In the first four weeks of the 110th, the “Magnificent Seven,” as the group is known, has produced several notable standouts, including GOP Sens. Jim DeMint (S.C.), David Vitter (La.), Richard Burr (N.C.) and John Thune (S.D.). The other members of the class of 2004, which meets once a month for breakfast or dinner to talk generally about upcoming policy issues, are Sens. Mel Martinez (Fla.), Tom Coburn (Okla.), and Johnny Isakson (Ga.), and they recently invited the lone 2006 Republican freshman, Sen. Bob Corker (Tenn.), to join them, said Burr.

Coburn has been active in the past two years fighting against earmarks in spending bills. Martinez and Isakson have proceeded with a lower-key approach to the chamber, and Corker is still getting his sea legs.

Still, Thune said they meet as a group with Senate GOP leaders to pressure them “in a friendly way” to incorporate their concerns and issues in the Republican floor strategy.

“We’re probably as organized a group as you get in the Senate,” said Thune, who noted that all seven are “pretty ideologically similar.”

Vitter said the unusual activity for a group that has been in the Senate for only two years reflects “our collective personality” and said he sees it as their response to a concern about “Republicans getting settled as the minority party.”

Senate Minority Whip Trent Lott (R-Miss.) said the seven are “filling the void” left by more experienced Members who either retired or lost re-election in the past decade. Lott said their activities are not being coordinated by leadership, though GOP leaders are not unhappy with their results so far.

DeMint, Thune and Vitter “are very strong on the floor. They’re bright, and they understand the legislative process, which makes them particularly effective. But they’re also very quick, and to be effective on the floor, you need to be quick,” said Sen. John Sununu (R-N.H.), when asked about the three.

Considering that all but Martinez — and Corker — served in the House of Representatives, Sununu said much of the group’s ability to maneuver comes from that experience.

“Service in the House helps because you have a sense of how much difficulty the House might have in dealing with any particular amendment,” he said.

That’s exactly the kind of strategy DeMint has been using — a tactic he described as, “We’re going to see you and raise you. … And then let them argue against themselves.”

The knowledgeable Senate Democratic aide conceded that Democrats were caught off guard during debate on the lobbying and ethics bill when DeMint, who recently was selected as the conservative Republican Steering Committee chairman, won a procedural vote on his amendment to implement more stringent disclosure rules on earmarks in legislation.

Noting that his amendment was supported by Speaker Nancy Pelosi (D-Calif.), DeMint and other Republicans ridiculed Democrats for trying to kill the proposal to require that even more earmarks to be disclosed, particularly after DeMint effectively received 51 votes for his amendment. Ultimately, however, Democrats were forced to accept DeMint’s proposal to avoid continuing bad publicity over the incident.

Meanwhile, Vitter frustrated leaders in both parties with his successful amendment banning Senate lobbying by the spouses and immediate family members of Senators. But he lost, 54-41, on a procedural move to kill his amendment to prohibit Members from hiring spouses and family members to run their political action committees.

Buoyed by a few wins on the lobbying bill, DeMint and his troupe kept up the heat on Democrats during last week’s minimum-wage debate as well, even as they say their coordination on tactics has been scant at best.

Democrats postponed a vote on a DeMint minimum-wage proposal to give themselves time to figure out a way to sink it without making their own Members appear opposed to even higher wages in certain states, Democratic and Republicans sources said.

Sen. Edward Kennedy (D-Mass.), who has been managing the minimum-wage bill on the floor, “saw right away that it was a poison pill,” said the knowledgeable Senate Democratic aide. “But he didn’t know if everybody else saw it the same way.”

DeMint’s amendment, which was killed on a procedural motion 76-18, would have forced states with wage laws higher than the current federal minimum to raise theirs by $2.10, just as those states that currently are implementing the existing federal standard would have to do in the underlying bill.

Meanwhile, Democrats have been loudly complaining about several other Magnificent Seven amendments that have been offered to the minimum-wage bill — such as a Burr proposal to allow employers to offer health insurance in lieu of a wage increase and a Vitter-Thune amendment to allow small business to band together to buy cheaper health insurance.

The Vitter-Thune proposal also has gotten the two in hot water with their own leadership, which has been trying to walk a fine line between demanding votes on GOP amendments and not being seen as blocking a minimum-wage increase by offering too many “poison pill” amendments.

Thune said he has been “getting a lot of resistance from our leadership” over the duo’s desire to have a vote on the amendment.

With Lott predicting that the group will be the next generation of Senate GOP leaders, Thune noted that they are likely to stay close throughout their tenure in the chamber.

“I think you could expect that kind of nucleus to hang together going forward,” he said.

Burr echoed that sentiment, saying, “This is evidence of the degree of activity you’re going to see from us from now on.”