The six republican presidential candidates will gather this evening in Des Moines for a debate, and front-runner George W. Bush will likely be the subject of barbs from his rivals. The candidates will get to question one another — and Steve Forbes says voters want to see whether Bush can stand the test.Forbes says tonight’s debate is important but not a make-or-break event for a candidate.During an appearance on Iowa Public Television, Utah Senator Orrin Hatch said he’s no slasher, but he plans to talk tonight about whether front-runner George W. Bush has what it takes to be President.During a Sunday appearance on the “Sam and Cokie” show on A-B-C television,Gary Bauer questioned whether Bush will stand up to tonight’s challenge.Arizona Senator John McCain will attend tonight’s debate, but has no other public events scheduled in Iowa as he’s not campaigning here. During an appearance on Fox News Sunday, McCain talked about getting rid of the ethanol subsidy and giving the money to poor parents who want to send their children to a private school.McCain is campaigning in New Hampshire, where the nation’s first primary will be held February 1st. Recent polls in that state show him ahead of Bush. Bush arrives in Iowa this afternoon. This is the third time the six candidates have shared the same stage in a debate.