Remember when Kevin McCarthy was regarded as a dutiful lieutenant likely to follow in the political and ideological footsteps of his mentor and long-serving predecessor, Bill Thomas? McCarthy served on Thomas' staff for a decade, so he surely picked up some of the congressman's instincts and more useful habits. He certainly inherited his boss's ability to win elections. But did he inherit his worldview?

The protege tag followed the likable, ever-youthful McCarthy to the state Assembly and stuck, even as McCarthy quickly ascended through the ranks and into Sacramento's Republican hierarchy, forging his own identity in the process. Elected to Congress upon Thomas' retirement at the end of 2006, McCarthy shot straight toward the top again -- and this time not as the leader of a borderline-impotent Republican minority, but as the No. 3 guy in a House of Representatives dominated by his party.

But this is not your mentor's Republican Party: The GOP has taken a hard right turn, leaving McCarthy and others in the GOP's House leadership to choose between flexible pragmatism and appeasement within their own ranks. Appeasement almost always wins.

How is McCarthy's GOP different from Thomas'? Take the matter of banning semi-automatic rifles. Twenty-four years ago, in a letter to a constituent, then-Rep. Thomas wrote: "I believe the sale and importation of weapons manufactured for military and anti-personnel use should be further restricted ... even if the availability of such weapons to law-abiding citizens is restricted in the process."

McCarthy, asked recently where he stood on such a ban, which has moved to the forefront of the national debate, said only: "I believe in the Second Amendment." Well, most of us do, Congressman. The question is interpretation.

Thomas was always rated "pro-life" by organizations opposed to abortion, although he voted to allow embryonic stem cell research at a time when many conservatives opposed it, and he opposed a ban on family planning funding in U.S. aid abroad.

McCarthy's record, though much shorter, is 100 percent "pro-life." But it's hard to get a straight answer out of him on one of the central questions of the debate: Does he support abortion in cases where the pregnancy was the result of rape or incest?

They differ even more on immigration reform. McCarthy gets an A rating from the anti-amnesty group Americans for Legal Immigration. A decade earlier, Thomas earned a zero from the Federation for American Immigration Reform, which also seeks to limit immigration: Thomas opposed a bill requiring that illegal immigrants who receive hospital treatment be reported to authorities, and he supported extending immigrant residency rules as well as increasing the number of visas for skilled foreign workers.

Are these men, hatched from the same incubator, really of such different minds? It's hard to say because they have played two very different leadership roles in two distinctly different eras.

As chairman of the House Ways and Means Committee at a time when the Republican Party was more moderate, Thomas, who served for 28 years, crunched policy and held sway over colleagues from both parties.

As whip, McCarthy is less about policy and more about party unity. He just happens to be trying to unify at a time when Republicans are disjointed, uncertain and, individually, worried about challenges from the right. That uncertainty has bubbled all the way to the top of the GOP leadership. It can be tough to flog rank-and-file Republicans toward unanimity on a given vote when the leadership hasn't given a clear signal about where it stands. No wonder it can be tough to get a straight answer out of McCarthy: He doesn't have a clear position because nobody has told him what it is.

What would Bill do? My guess: Thank God he's retired.

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