The Senate Tea Party Caucus is scheduled to launch today. But its mission and potential for political and legislative influence in an independent-minded chamber governed by personal relationships remain open questions.

Already, a handful of freshman Republicans who garnered the backing of tea party activists in 2010 have declined to join or claimed to have given the matter little thought. And some veteran GOP Senators, while expressing strong support for tea party principles, doubted the group’s ability to affect policy.

“I haven’t seen a caucus in the United States Senate that met, much less got an initiative, because I think that the Senate, institutionally, is so different than the House,” Sen. Richard Burr (R-N.C.), a former House Member, said Wednesday. “I think it’s good and healthy for the advocacy. But from the standpoint of actually the work that’s going to be done and the impetus behind moving a majority of the Members in one way, I think the personal relationships over here have a much better impact.”

But, weather permitting, the Tea Party Caucus will meet at least once, at 10 a.m. today in Room 216 of the Hart Senate Office Building. The group is led by its three inaugural members, Republican Sens. Jim DeMint (S.C.), Mike Lee (Utah) and Rand Paul (Ky.), who was the driving force behind the caucus’s formation.

DeMint is chairman of the Senate Republican Steering Committee, which has unofficial jurisdiction for all things conservative within the GOP Conference. Whether a Republican Senator is looking to get a conservative piece of legislation to the floor or influence the Conference message in that direction, the Steering Committee has long been the vehicle to accomplish those goals.

DeMint said a thriving Senate Tea Party Caucus would not change that, explaining that the new group is intended to function as an “external” arm of the Steering Committee that will focus on outreach to voters, including conservative and tea party activists. DeMint, who throughout the 2010 cycle supported the tea-party-backed Republicans now in the Senate — sometimes to the dismay of GOP leadership — stressed that the group remains a work in progress.

“We don’t know exactly how the Tea Party [Caucus] is going to work yet. We just want to open the door and make sure that folks who helped get us elected know that we want to be their voice and listen to what they’re saying,” he added, just before convening Wednesday’s weekly Steering Committee meeting. “What we have to do is prove that this is a legitimate tea party effort.”

Paul was hesitant Wednesday to comment on the new caucus. But Lee said the aim of the group is to provide a “conduit” for information between tea party activists and his fellow Republican Senators. Lee won last year after three-term incumbent Sen. Bob Bennett failed to make it past the Utah GOP state convention and onto the primary ballot. He was targeted by tea party activists and other groups who charged he had not been fiscally conservative enough.

“We don’t purport to speak for the tea party. It remains an organic, grass-roots movement, a political phenomenon more than anything, and it will remain such under this,” Lee said.

Conservative tea party activists played somewhat of an influential role in several competitive GOP Senate primaries, and the tea-party-backed nominees had mixed success in November. Among those who were victorious were GOP Sens. Ron Johnson (Wis.), Marco Rubio (Fla.) and Pat Toomey (Pa.), in addition to Lee and Paul. Sen. Jerry Moran (R-Kan.) was also endorsed by DeMint in his competitive primary, and the South Carolinian traveled to Kansas to campaign for him.

But that hasn’t translated into Tea Party Caucus membership, at least not yet.

Moran said Wednesday that he has been focused on getting his office up and running and has “no particular thoughts at the moment” on the matter, while Toomey said he is looking forward to learning more about it. Johnson, however, has made a conscious decision not to join, and he did not shy away from discussing his reasons.

“I sprang from the Tea Party and have great respect for what it represents. The reason I ran for the U.S. Senate was to not only stop [President Barack Obama’s] agenda but reverse it. I believe our best chance of doing that is to work towards a unified Republican Conference so that’s where I will put my energy,” Johnson said in a statement provided to Roll Call.

Rubio, meanwhile, said he remains on the fence.

“We do have something called the conservative steering committee, it’s been there for a while, run by Jim DeMint. … I’m going to be joining that,” he told the Shark Tank, a Florida political website. “But what I’m kind of curious to figure out in consultation with these other Senators who are involved in the tea party caucus [is] ‘Why do we need something in addition to the steering committee?’”

Separate caucuses, although common in the House, are rare in the Senate, and the Republican Conference leadership tends to be cautious of political sub-groups that could vie for influence among the rank and file. But in the case of the Tea Party Caucus, leaders have declined to express concern, and in fact, they might not have any.

Two senior Republican Senate aides connected to the leadership team agreed that the group could be helpful, while noting that GOP Senators share the core beliefs of the tea party movement.

“Our opinion is that any outreach from Republican Senators to any group of American voters is a plus for all Republicans in Congress,” one of the aides said.

However, skepticism was exhibited by some institutional-oriented Members, including Sen. Roy Blunt (R-Mo.), who said he is not “much of a caucus joiner” and argued that the GOP minority would probably function better if Senators focused on the Conference as a whole.

But Sen. Orrin Hatch, who faces the likelihood of a Bennett-like convention challenge in 2012, said the Tea Party Caucus could prove beneficial to his colleagues.

“I think it’s a good idea for people to get together,” the Utah Republican said. “I think the tea party has been a great deal in this country. It’s helped to bring about a little bit of a transformation this time, and hopefully it’ll get better.”

Jackie Kucinich contributed to this report.