During the oral arguments last year in the U.S. Supreme Court case that sought to invalidate the Democratic health care law, Mike Lee watched from a familiar vantage point. The first-term senator from Utah has been witnessing high court arguments from inside the chamber since he was 10 years old. To him, the place was less an intimidating fortress on the Hill than a neighborhood clubhouse.

His father, Rex Lee, was the legendary solicitor general in the Reagan administration who argued before the court some 60 times in his career. While other fathers and sons talked sports at the dinner table, Mike and Rex Lee discussed issues of constitutional law and federalism. "I remember asking about Roe v. Wade," Lee recalls in an interview in his Senate office, where he has named a conference room after Rex. "Why was that a federal issue? Why is that not an issue for the states?"

When told that was an unusual question for a young boy to ask, Lee laughs: "I was 30 before I realized every family doesn’t talk about the presentment clause over dinner."

But last year, Lee wasn’t in the chamber for the health care arguments out of sentimentality, nor was he there purely out of intellectual curiosity. As one of the most conservative members of Congress, his presence was an act of political resistance. And the court’s eventual decision in the case still leaves a bitter taste in his mouth."We can’t overlook what we lost that day," he says.

Lee, 41, has credentials beyond that of a standard-issue partisan warrior. He’s a former assistant U.S. attorney and appellate lawyer who clerked for Samuel Alito (who had worked in the SG’s office under Rex Lee) on the U.S. Court of Appeals for the Third Circuit and later, when Alito became a justice. Lee, along with the recently elected Ted Cruz of Texas, represent a new genus of Republican senator. The men are scions of the conservative legal movement who have decided to use politics, not courts or think tanks, as their platform. In a sense they’re ideal foils for the Harvard Law School–trained constitutional scholar who currently resides in the White House.

Like Lee, who is a close friend, Cruz, 42, is a lawyer first. The son of a Cuban immigrant father, he was a top editor of the Harvard Law Review and became the first Latino to clerk for a chief justice when he worked for William Rehnquist. He helped shape counterterrorism policy as part of John Ashcroft’s U.S. Department of Justice in the months after the 9/11 attacks, and then returned to Texas, where he became the state’s solicitor general. There, among other things, he defended Texas’s Ten Commandments monument at the state capitol that was accused of violating the First Amendment, challenged "Obama­care," and argued for Second Amendment gun rights. Before his election to the Senate last year, he had argued in front of the justices nine times and written dozens of Supreme Court briefs. (Both Lee and Cruz have also done stints in law firms, Lee with Sidley Austin and Howrey, and Cruz with Morgan, Lewis & Bockius.)

As the GOP struggles to find a way forward in the wake of President Barack Obama’s reelection and electoral setbacks in the Senate, Cruz and Lee, along with the libertarian-leaning Rand Paul of Kentucky and Florida’s Marco Rubio, have infused the party with new contrarian combativeness. John Geer, a political science professor at Vanderbilt University, says they’re part of a classic battle of "purists versus pragmatists" that occurs after a party loses a major election.

But not everyone—including those within the party—is a fan. After Paul’s into-the-night filibuster over drone policy, John McCain called Paul and Cruz "wacko birds." And Cruz, in particular, has given some reason for pause. The time-honored advice to new senators, especially ones with some celebrity pedigree, is to be more of a workhorse in the early months and less of a show horse. But he has upended that notion by regularly appearing on cable news and showing up frequently in the press. In the early days of his tenure on the Senate Judiciary Committee, he picked an ugly fight with Attorney General Eric Holder over drone policy in which he suggested that Holder would sanction killing U.S. citizens on American soil as if they were just "sitting at a café."

Most notably, Cruz and Lee have melded their courtroom-trained advocacy with the sharp-edged and often hyperbolic rhetoric of the Tea Party movement. "We have a federal government that thinks they have the authority to regulate our toilet seats and our lightbulbs," Cruz told an adoring crowd at the Conservative Political Action Conference in Washington, D.C., this spring. Lee used his time at the conference to appeal to the crowd for the values of a "civil society" that rejects the notion of a large federal government. "Over the past 80 years the federal government has expanded well beyond its constitutional limits," he said. "The history of progressivism demonstrates that as the power of the federal government increases, the ability to self-govern ­diminishes."

The duo is a natural outgrowth of the conservative forces within the legal establishment that have long been trying to take constitutional doctrine back to its pre–New Deal state, with its more limited view of federal power, something that mixes well with their libertarian-influenced philosophies. But they can, at times, clash with their own party: Along with their jaundiced view of the drone program, both Cruz and Lee object to allowing the Pentagon to indefinitely detain suspected terrorists without trial.

As a legislator rather than a litigator, Lee views his function in the Senate as serving as much a check on his colleagues as a check on other branches of government.

"Not every power should be exercised on the federal level," Lee says, a copy of The Federalist Papers on a coffee table in his office. "Members [of Congress] need to be conscious of those limitations. Our powers were designed to be limited. Those limits have to mean something."

Vanderbilt’s Geer says Cruz and Lee’s worldview has limited electoral reach. "People like the idea of returning to the Founding Fathers until they find out what that means," he says. He adds, however, that their youth gives them a great political advantage. They aren’t hamstrung by the outdated attitudes of the last generation of Republican leaders, and they have a modern grasp of a multicultural American society. "That’s critical," Geer says. "That makes them more dangerous in terms of being effective."

With both Lee and Cruz on the Judiciary Committee, they are likely to play significant roles in ongoing debates over counterterrorism policy, immigration, privacy, and gun control. And should a Supreme Court justice retire in the coming years, it’s likely they’ll be among the party’s leading cross-examiners of any nominee.

But then, given their age and backgrounds, they could also be possible picks for the high court itself when a Republican at some point regains the presidency. The question, given the ambitious nature of both men, is whether that will be enough.

Oliphant is a Washington, D.C.–based journalist who writes on the intersection of law and politics.