If it's Monday, it must be Phoenix.

The merry-go-round of presidential debates continues tonight when the six Republican candidates meet for the second time in five days. But this time, the candidates will get to question one another.

Last Thursday the six debated in Manchester, N.H., the first time Texas Gov. George W. Bush joined his fellow candidates. Tonight the debate will be held in Phoenix. Five candidates will appear on the stage of the city's Orpheum theater.

Arizona Sen. John McCain, a late addition to this recently scheduled debate, will participate by satellite from Boston. Despite facing serious competition from Bush in his home state, McCain almost missed the debate, claiming scheduling conflicts.

The 60-minute debate will air nationally on CNN, beginning at 8 p.m. It will be held before a live audience. In the first half-hour, CNN correspondents will ask the questions. In the second half-hour, candidates will ask the questions. One-minute closing statements will conclude the event.

Bush survived his debut as a presidential debater but did not dominate the 90-minute event on Thursday. His performance in New Hampshire may embolden some of his rivals to push even harder than they did on Thursday to expose weaknesses in the GOP frontrunner.

After Thursday's debate, magazine publisher Steve Forbes, who has been the most aggressive in trying to draw distinctions with Bush, said he believed continued exposure by the frontrunner would make him a less attractive candidate to Republican primary voters.

"It will be the accumulation of debates that will make the impression," Forbes said in an interview.

Until late last week, it appeared McCain would not participate in the debate, even though a victory in his home state is crucial to his hopes of overtaking Bush. The Texas governor has mounted a stiff challenge to McCain in Arizona.

McCain has the support of many top elected officials in Arizona, but there are some notable exceptions, led by Gov. Jane Hull. It was Hull who helped start the round of stories about McCain's temper. Over the weekend she said she believes the issue has been "exaggerated."

Campaigning in New Hampshire this morning, McCain said he would shut down the federal government if necessary to curb pork barrel spending. "If we don't change business as usual in Washington, people will be deprived of their representation," he told a town hall meeting.