WASHINGTON – Can Rick Perry rebound from a troubled September? How will Herman Cain endure his first test as a heavily scrutinized candidate? And will Mitt Romney, debating in a state where he’s a strong favorite, stay on his cool, steady course?

Those are the key questions as the Republican presidential candidates meet again tonight in Hanover, N.H., for their first debate in 19 days. The topic is supposed to be economic issues. The debate begins at 8 p.m. EDT and will be televised nationally by Bloomberg TV.

The encounter, about three months before the first-in-the-nation New Hampshire primary, is likely to matter in small but important ways.

“People don’t know any of these people well,” said Peter Brown, assistant director of the Quinnipiac University Polling Institute, which conducts national surveys. Debates are a chance for voters to get familiar and comfortable with candidates.

New Hampshire voters are already familiar with Romney, who was governor of neighboring Massachusetts, has a home in Wolfeboro, N.H., and finished second in the state’s 2008 Republican presidential primary with 32 percent.

Romney remains the unquestioned New Hampshire favorite. In the WMUR Granite State poll conducted Sept. 26 to Oct. 6, he was the choice of 37 percent of likely Republican voters. Cain, the business executive who vaulted to prominence last month by winning the Florida GOP straw poll, was next, at 12 percent.

Trailing were Texas Rep. Ron Paul at 9 percent; former New York City Mayor Rudolph Giuliani, who is not expected to enter the race, at 8 percent; former Utah Gov. Jon Huntsman, 8 percent, and former Texas Gov. Perry, 4 percent.

But 86 percent of likely Republican voters said they are extremely or very interested in the race, and 68 percent said they were still trying to decide on a candidate.

“Most people don’t make up their minds till the end,” said Andrew Smith, director of the University of New Hampshire Survey Center.