The caucus of the most conservative senators has chosen a new leader. It’s not either of the Republicans who will probably come to mind first — but he may well be the man who’s going to push the Senate hardest to the right over the long term.

Mike Lee of Utah will take over as chairman of the Senate Steering Committee in January. That means he’ll be among the most influential conservatives at the Capitol in the run-up to the next presidential election. If his side wins at least six of the seats it’s after this fall, Lee will be positioned to play a central role in assembling and advancing the legislative agenda of a newly Republican Congress.

For at least a few months into next year, Lee looks destined to remain routinely overshadowed by Rand Paul and Ted Cruz, his partners in the informal triumvirate of libertarian-minded junior senators with monosyllabic names.

For the past couple of years, those two have been far more intentional than Lee about generating publicity for their confrontationally conservative crusades. Their dedication to self-promotion will only intensify if they keep moving toward presidential bids, which means the Senate floor in early 2015 could become the principal venue where the Kentuckian and the Texan test potential planks for their national platforms.

But that approach only works for so long, as others who have sought to move from the Capitol straight to the White House have learned. For one thing, it’s difficult for the Senate floor to be a campaign soundstage for more than one member at a time, especially after the inevitable rivalries among the nationally ambitious come into the open. For another, lawmakers who gain some early traction in the fundraising and Beltway-attention-getting stages of the process soon enough realize they have to spend much less time on the Hill and more time on the hustings.

This is why Lee now seems well-positioned to fill an impending power vacuum.

Both Paul and Cruz may effectively be on indefinite sabbatical from the Senate a year from now, clearing the conservative limelight at the Capitol for their lesser-known partner. If one of them ends up as president, he would presumably look to Lee as an essential legislative helpmate. It’s far from clear the Kentucky Legislature would change state law so Paul could be the GOP nominee for both president and a second Senate term in 2016, and if he fails to secure the nomination he might have to confront an intense fight for re-election. Cruz’s term isn’t up until 2018, but it’s possible he might choose to trade in his polarizing supernova life in Congress for an opinion leader’s platform outside government.

Any of those scenarios would allow the new Steering Committee head to become the de facto dean of the new generation of Senate GOP conservatives before his first term in deeply red Utah ends — and to remain in that pivotal role for many years.

Lee will take over the panel from Patrick J. Toomey of Pennsylvania, who is stepping aside after just two years. Toomey is anticipating a tough fight for a second term in his swing state in 2016, and remaining the titular leader of the Senate’s most conservative Republicans wouldn’t endear him much to the independents and Democrats he’ll be wooing.

At the same time, Toomey has infuriated many on the right because of his efforts last year to craft and sell the bipartisan Senate gun control compromise — a sharp reversal for someone who movement conservatives loved during his previous career running the low-tax, free-market Club for Growth.

The right can count on “less accommodation and more resistance” in the Steering Committee’s dealings with Democrats under Lee, the conservative redoubt Human Events said in an effusive post on Wednesday. Not to mention, the post read, “less cooperation with the GOP Senate leadership and greater clarity for the American people about who is really fighting for them. One thing we will not see starting in January is the leader of conservative senators carrying water for the president.”

Lee’s regular outlet for influence will be hosting the weekly Steering Committee lunch, which now routinely draws more than half the 45 members of the GOP Conference. Especially under the chairman before Toomey — Jim DeMint of South Carolina, who resigned his seat in 2012 to take the helm of the Heritage Foundation — those Wednesday sessions were often where rank-and-file Republicans hatched more combative plans than what their leadership espoused at caucus lunches the previous day.

At 43, Lee is the youngest GOP senator, and his rise has already been unusual and fast. He was a herald of the 2010 tea party wave when he ended Sen. Robert F. Bennett’s bid for the GOP nomination to a third term. Before that, Lee was the head of appeals litigation in the Salt Lake City office of a prominent law firm after stints as a federal prosecutor and a senior gubernatorial aide in Utah, interspersed with clerkships for Samuel A. Alito Jr. on both the Supreme Court and the federal appeals court in Philadelphia. To the extent he was known to veteran insiders in Washington, D.C., it was as the precocious teenager who attended dozens of the oral arguments at the high court where his father, Rex Lee, represented the Reagan administration as solicitor general.

Given that back story, it is little surprise the adjective often used to describe Lee’s senatorial persona is “lawyerly.” And he cultivates that reputation by answering many questions at paragraph length. While he can rattle off the party’s talking points of the day with ease, he just as often unfurls a series of fact-filled and well-thought-through dependent clauses.

That’s why Lee’s role as a conservative spur is less well-documented than his more telegenic partners’. But he has joined them at virtually every assertive turn. Cruz was undoubtedly the biggest salesman of the shutdown strategy of a year ago, but the evidence shows it was Lee who first proposed, in the summer of 2013, that uninterrupted funding for the government be conditioned on a defunding of the health care law.

In the new year, he is poised to stand alone in the Senate as the right’s litigator in chief.

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