While the Democrats mostly attacked President Bush, the Republicans are likely to take aim at each other during their nationally televised encounter at the Ronald Reagan Presidential Library in Simi Valley, Calif. That will be probably be encouraged by moderator Chris Matthews of MSNBC, who is planning to throw "zingers" at the candidates in an effort to force them to make news, according to a well-placed source with one of the major contenders.
Several of the lesser-known hopefuls, such as former Virginia Gov. Jim Gilmore, are already criticizing their opponents for not being "true conservatives." Rep. Tom Tancredo of Colorado is running largely on a theme of cracking down on illegal immigration, and he is expected to confront his rivals for not tackling this issue head-on.
One open question is how much the front-runners will draw contrasts among one another.
That's been happening more and more on the campaign trail, and Thursday's debate will offer a high-visibility forum to drive those differences home. Some political insiders predict that John McCain and Mitt Romney will attempt to criticize front-runner Rudy Giuliani in an effort to slow his momentum and boost their own chances. It's also considered likely that the candidates will try to separate themselves in some ways from President Bush, who has become an unpopular figure with independents and Democrats.
Even Republicans are looking for a change. The latest Pew Research Center poll found that 54 percent of Republican and Republican-leaning voters want a presidential candidate who will take a different approach to the Iraq war from Bush's.
Another prediction from GOP insiders: The presidential candidates will open fire on majority Democrats in Congress for allegedly showing weakness on Iraq and national security and for moving in a leftward direction on spending and other issues.
"That much the [Republican] candidates can agree on," says a prominent former adviser to President Bush.
By Kenneth T. Walsh