PRESIDENT BUSH IS A CONSERVATIVE politician, not a conservative ideologue. This explains why Bush sometimes does things that aren't conservative. He does so to survive and, if all goes well, to prosper politically. Or he does so because he actually favors some nonconservative policy or position. Conservative politicians are never ideologically pure. "The president works at 1600 Pennsylvania Avenue, not 214 Massachusetts Avenue N.E.," a Bush administration official says. The Massachusetts Avenue location is the site of the Heritage Foundation, the conservative think tank.

President Reagan, like Bush, was a politician first and an ideologue second. When Social Security was on the verge of insolvency in 1983, he had to act quickly. But he didn't call for benefit cuts or privatization, the conservative positions. That was not politically feasible. He agreed to a tax hike and a modest increase in the age of eligibility. And the issue went away, leaving him politically undamaged and able to pursue his conservative goals, like winning the Cold War.

Calling for a probe of oil companies for possible manipulation of gas prices is Bush's latest nonconservative position. With prices soaring, he was losing ground politically. The public and the politicians, Republican and Democrat alike, were attacking the oil companies--and Bush as well. His job approval rating dipped into the low 30s, the worst of his presidency.

He could have said, no, the free market is working properly. That, while basically true, would no doubt have further injured his political standing. Instead, he moved to take control of the issue and protect himself politically. Two days later, the president conceded he had "no evidence that there's any ripoff taking place." Of course he hadn't. That wasn't the point of his intervention.

His divergence from conservative orthodoxy was probably harmless. "I don't think there's any problem in looking into the possibility of price gouging," the administration official says. "If it doesn't exist--and the odds are quite strong it doesn't--nothing will be lost." In fact, the president gained politically. His approval rating in the Fox News poll rose from 33 percent to 38 percent.

Neither Bush nor White House officials have suggested, publicly at least, that there's a paradox involved in taking nonconservative positions on issues such as gas prices. But it's true that this may shore up the president's popularity and enhance his ability to pursue conservative issues like the war on terror, Iraq, and tax cuts.

Besides political expediency, conservative politicians sometimes stray because they've become enamored of a nonconservative position for policy or political reasons, or both. Reagan wanted to eliminate all nuclear weapons in the world, despite their deterrent value. He insisted on picking a woman, moderate Sandra Day O'Connor, as his first Supreme Court nominee. He met repeatedly with Soviet leader Mikhail Gorbachev. Conservatives fumed.

Bush's chief apostasy is on the Medicare prescription drug benefit, the first new entitlement in decades. Rather than aiding only needy seniors--perhaps a quarter of the over-65 population--he championed a far more expensive universal benefit. Bush touted it in the 2000 campaign and pushed it aggressively in Congress. It was enacted in December 2003 and implemented this year.