2nd GOP presidential debate: It's rematch time

This should be fun.

Republican presidential candidates gather Wednesday in Simi Valley, Calif., for the second debate of the political season.

The first debate, hosted by Fox News in Cleveland on Aug. 6, was the highest-rated telecast in the channel's 20-year history, snagging the attention of 24 million viewers. The first Republican debate four years ago, by comparison, attracted 3.2 million viewers.

In round one, Donald Trump dominated and fended off parrying from his opponents — several of whom have promised to take him on more directly this time around — and from moderator Megyn Kelly.

Carly Fiorina, a former business executive — and the only woman in the GOP contest — made a strong showing in the undercard last month and will join the top-tier debate at 7 p.m. Twin Cities time.

The earlier forum for candidates ranked lower in polls begins at 5 p.m. and will be a diminished affair: Former Texas Gov. Rick Perry dropped out of the race on Friday and former Virginia Gov. Jim Gilmore didn't qualify because of his low poll ratings.

This time around, candidates will not give opening or closing statements. They'll each have a 15- to 20-second window to introduce themselves to viewers.

But here are the upcoming dates that really matter: Iowans will caucus on Feb. 1, 2016, and the first-in-the nation New Hampshire primary is scheduled for Feb. 9.

The pressure is on top-tier candidates to break out from the crowded field.

Jeb Bush

The spark that his supporters had hoped to see in the first debate wasn't there. Since then, he's been taking mild pokes at Trump, showcased a sense of humor on Stephen Colbert's late-night debut and rolled out some serious policy proposals. But he needs to stop his slide. His big warchest, which he's begun to deploy to buy TV ads, will keep him in the mix.

Ben Carson

Chris Christie

The New Jersey governor joked that he's going to "go nuclear" at Wednesday's debate if he doesn't get his fair share of questions. Once considered a formidable presidential prospect, he's now pulling single-digit support in national polls. He's trying to boost his campaign with TV ads that focus on his record and recently noted that the first votes are still months away.

Ted Cruz

He's been echoing some of Trump's views and shared a stage with him last week at a rally opposing the Iran nuclear deal. There's a sense that he's positioning himself to pick up Trump's support if and when the frontrunner's campaign unravels. But what if it doesn't?

Carly Fiorina

Mike Huckabee

There he was last week, standing next to Kim Davis, the Kentucky county clerk who had been jailed for refusing to issue marriage licenses to same-sex couples. The move epitomized his campaign's focus on Christian conservatives — who are a powerful bloc among Iowa Republicans.

John Kasich

He was considered a long shot before the first debate, but was praised for parrying Trump and showcasing his conservative message. His showing won him more donations, a second look from many voters and higher poll ratings. As a result, expectations for him are high in this week's debate.

Rand Paul

Marco Rubio

He's still young, still energetic, still has an appealing personal story and is still admired by conservative voters. But he's stuck in the middle of the pack with dwindling poll numbers. If he can steal — or at least share — the spotlight on Wednesday, it might not be too late for a surge.

Donald Trump

His outrageous comments (last week he insulted Carly Fiorina's appearance) and unabashed lack of knowledge on foreign policy and other matters haven't made a dent in his popularity. Debate moderator Megyn Kelly was tougher on him in the first debate than his opponents were; will they rough him up this time?

Scott Walker

Lower poll ratings landed these candidates in the early forum.

He seems to be having a blast on the campaign trail and can come across as wise and witty in his frequent cable TV appearances, but his message is downbeat. He supports a U.S. military invasion of Syria to oust its leader, would send U.S. ground troops back to Iraq and says Americans need to make more sacrifices. "We're going to do the hard things," he said at the Iowa State Fair.

In just the last few days, he's gone on the offensive against Trump, calling him an "egomaniacal madman" and a "carnival act." Trump took the bait, firing back that he only responds to "people that register more than 1% in the polls." Assertiveness might get this Louisiana governor noticed, but it could take more than that to ignite his candidacy, which hasn't lived up to expectations.

The former New York governor is struggling to crack 1 percent in the polls. If he's going to catch on anywhere, it probably will be in New Hampshire, where he's spending a lot of time. He explained his strategy last month, saying that after a summer of "reality theater politics," voters eventually will seek out a candidate "who can actually lead the government."

Who won the Iowa caucuses in 2012? That's right, this former Pennsylvania senator, a reliable conservative, did. He also won several primaries and finished second in the nominating contest to Mitt Romney. Has that strong showing helped him this time around? Nope. He's banking on Iowa again and just became the first 2016 hopeful to visit all 99 of the state's counties.

They will not be on the debate stage Wednesday.

Who  ? Exactly. The former Virginia governor is dead last in most polls — a sure recipe for a fundraising drought — and hasn't found a way to distinguish himself. He was in the lower-tier Aug. 6 debate, but he didn't meet CNN's requirement of earning at least 1 percent in three polls to qualify for Wednesday's debate. Not a good sign for his campaign.