The Republican road show comes to Iowa tonight, with the third presidential debate in less than two weeks among the six GOP candidates.

Round three offers Texas Gov. George W. Bush the chance to redeem himself after two debates that have drawn criticism about his performance. Bush is under pressure to take command of the debate, rather than to continue with his campaign's strategy of attempting to remain above the fray.

The 90-minute forum also gives Arizona Sen. John McCain a chance to make his case before Iowa voters. McCain is not formally competing in the state's Jan. 24 precinct caucuses, but a surprise finish here could boost his candidacy further in New Hampshire, where he now leads Bush in several polls.

Magazine publisher Steve Forbes also hopes to take advantage of tonight's debate. He is staking his candidacy on a strong second-place finish in Iowa, but will need a spark to get his campaign moving.

Tonight's debate will run from 8 p.m. to 9:30 p.m. EST and will air nationally on the cable network MSNBC.

The format will be similar to that of last week's debate in Arizona. The candidates will take questions from the two moderators, NBC News anchor Tom Brokaw and John Bachman, the anchor at WHO-TV in Des Moines, the station that is sponsoring the debate.

But the candidates also will be able to question one another. Last week most of the candidates asked relatively easy questions of one another, but this week's forum might produce more pointed exchanges.

Conservative activist and former Reagan administration official Gary Bauer said Sunday he would like to question Bush about abortion, specifically whether Bush believes the Supreme Court's decision in Roe v. Wade was correctly decided.

Bauer, challenging Forbes in Iowa for support of religious and social conservatives, said that while Bush remains the favorite to win the Iowa caucuses, he also believes "there's a 50-50 chance that in the next five weeks he's going to go into meltdown in Iowa."

Two other candidates, former diplomat Alan Keyes and Utah Sen. Orrin Hatch, also challenged Bush during Sunday morning talk show interviews. Keyes said Bush's failure to take a stronger stand against abortion was troubling.

Hatch, who quipped in last week's debate that Bush should spend four or eight years as Hatch's vice president to gain more experience, continued to promote his own experience as making him most qualified to be president.

Bush holds a solid lead in recent Iowa polls, with nearly 50 percent of the support of Iowa Republican voters. But in past presidential campaigns, the best any Republican candidate has done in the caucuses is 37 percent of the vote. Four years ago, Bob Dole won the caucuses with just 26 percent.