The announced Republican candidates for president did nothing in their first debate to discourage the unannounced Republican candidates — Fred Thompson, Newt Gingrich, maybe Chuck Hagel — from wading in. The water doesn't look very deep.

Lined up on stage at the Ronald Reagan Presidential Library last Thursday, each of the 10 presidential hopefuls struggled to distinguish himself from the crowd. Even if you knew Tommy Thompson from Jim Gilmore from Mike Huckabee, it was hard to keep them straight. "Diverse" certainly wasn't a word that came to mind when you looked at the field. I admit that my first thought was "country club."

Of the three front-runners, former Massachusetts Gov. Mitt Romney had the best evening, in my estimation. Looking back at my notes, I find that he didn't actually say much — he promised "leadership," he admired Reagan's sunny optimism, he labeled House Speaker Nancy Pelosi, Senate Majority Leader Harry Reid and Sen. Hillary Clinton as "the Gang of Three."

But he looked great. The luck of the draw placed Romney right next to host Chris Matthews, which meant he got to go first on the round-robin questions; he took advantage, filibustering capably. And Romney has the best hair, by far, of any of the Republican candidates. It's John Edwards-level hair. Someone should check how much he pays for his haircuts.

Romney also came prepared with an explanation of how he switched from an abortion-rights position to being anti-abortion. His Road-to-Damascus moment came two years ago, he explained. As governor, he had to develop a position on human cloning; his research into the implications of bioengineering led him to conclude that abortion was wrong.

Romney's story may not be watertight, but at least it's better than Rudy Giuliani's. Basically, the former New York City mayor is for abortion rights. But that's not something you want to advertise to Republican primary voters, so Giuliani tried to draw the finest of distinctions. "I hate abortion," he said, giving the impression that he believes abortion is wrong. But he also "would respect" a woman's right to "make a different choice." And anyway, he said, the decision should be left up to the states.

But that makes no sense. If abortion is such a horrible practice, why let any state allow it?

Giuliani's worst moment came when he was asked what he would think if Roe v. Wade were overturned. "It would be OK," Giuliani said.

Most people would consider the demise of Roe v. Wade either a catastrophic infringement of women's sovereignty over their own bodies, or an end to the practice of mass murder. Few would be so indifferent as to shrug and say "OK." On abortion, the tough-talking Giuliani seemed incongruously meek.

There was no meekness, though, from John "Gates of Hell" McCain — that's how far he said he'd pursue Osama bin Laden. All the major candidates displayed some degree of hawkishness, but McCain has hitched his wagon to President Bush's troop "surge" and so he went out of his way to come off as an uber-hawk.

The war in Iraq was "terribly mismanaged," McCain said, but now it's "on the right track." When House Democrats celebrated the passage of an Iraq spending bill with timetables for U.S. withdrawal, McCain said, "What were they cheering? Surrender? Defeat?"

Given the unpopularity of the war — and the unpopularity of its author, the incumbent Republican president — I'm not sure the usual Republican technique of portraying Democrats as weak on security is such a promising strategy this time. But aside from Rep. Ron Paul, who doesn't like foreign entanglements, all the Republican candidates followed the playbook and portrayed themselves as from Mars and the Democrats as from Venus. No one seemed to have a better idea.

Try as each man might to cloak himself in Reagan's mantle, it didn't seem to fit. As candidates, they all seemed to have some growing to do.

Eugene Robinson is part of The Washington Post Writer's Group. Reach him at eugenerobinson@washpost.com.