WASHINGTON - Although dozens of Republicans sailed into office with the help of the tea-party movement last year, finding a self-identified "Tea Party Republican" on Capitol Hill is harder than you'd think.

The first meeting of the Senate Tea Party Caucus on Thursday attracted just four senators - out of a possible 47 GOP members - willing to describe themselves as members. The event was as notable for who wasn't there than who was.

• Sen. Marco Rubio, R-Fla., once a tea-party darling, has for now declined to join the caucus, whose first meeting was organized by Sen. Rand Paul, R-Ky.

• Sen. Ron Johnson, a Wisconsin Republican whose campaign sprang from the small-government movement, has passed for now.

• Sen. Pat Toomey, R-Pa., showed up to address the group of activists Thursday, but then hustled out of the room, ignoring reporters' questions about whether he was in or out.

The reluctance shows how the purposefully disjointed movement and its crop of outspoken and controversial leaders, although a powerful force in a campaign known as the "year of the tea party," are still viewed as risky allies even for conservative politicians.

With the rhetoric of the campaign now translating into politically painful budget cuts, the tea-party agenda looks less like the hub of Republican energy in Congress and more like an endpoint of the spectrum.

To be sure, there are institutional reasons for the Senate Tea Party Caucus' still-meager membership. In the House, special-interest caucuses serve as a way for like-minded lawmakers to amplify their influence. But in the Senate, which has fewer members, the tactic is less necessary, and senators are less eager to join.

The Senate also has a stricter pecking order and a more defined set of expectations for new members.

So it was fairly unusual when, after just a few weeks in office, Paul proposed his own budget. He recommended gutting the Interior and State departments, eliminating the Department of Energy and cutting all funding for public radio and television and the National Endowment for the Arts.

While Paul's plan cuts $500 billion from the budget in a year - five times what Republican leaders in the House have proposed - it's not one even some fiscally conservative Republicans have been quick to endorse.

A spokesman for Rubio, a former Florida state lawmaker who edged out Gov. Charlie Crist in a three-way race, said the senator hasn't read it. Rubio's own plan for overhauling education contains no specific program cuts.

Paul's approach - bold, specific and unwaveringly conservative - is exactly what the most engaged activists of the tea party have been seeking. One of the biggest applause lines at Thursday's meeting came when staunch conservative Sen. Jim DeMint, R-S.C., quoted Paul as saying, "My goal is to make DeMint look like a moderate."

But it's not necessarily a pragmatic approach for lawmakers such as Rubio or Johnson, who need to attract support from independent and even Democratic voters in their swing states.

Johnson said he was declining for now to join the Tea Party Caucus because it threatened to highlight division among Republicans.

"The reason I ran for the U.S. Senate was to not only stop the Obama 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," said Johnson, who noted that he had "great respect for the tea-party movement."