5 Things to Watch for at the Houston Republican Presidential Debate

— -- The five remaining Republican presidential candidates will take the stage in Houston tonight for the final debate before Super Tuesday.

The stakes may have been high at previous debates, but nothing like tonight. Donald Trump will take center stage and likely come under heavy fire. Meanwhile, both Marco Rubio and Ted Cruz need to try and slow down the Trump Train by getting in clean jabs at the front-runner and generating memorable moments.

Here’s a look at five things to watch for at the debate, sponsored by CNN and Telemundo and held at the University of Houston:

1. Trump, The Middle Man

Trump has occupied the prime position at most of the other debates, but as the man in the middle once again, he will have a major target on his back -- perhaps bigger than ever before.

Poised to do well on Super Tuesday and beyond, the other candidates need to throw some major obstacles in his path to the nomination.

Trump’s trifecta of first place finishes in New Hampshire, South Carolina and, most recently, Nevada, has led some GOP strategists to wonder aloud whether the other candidates were taking on Trump aggressively enough. We’ll see how hard they hit tonight.

2. Taxing Questions

It's very likely Trump will face questions about his taxes after 2012 GOP nominee Mitt Romney floated the idea on Fox News yesterday that there is possibly a "bombshell" in them.

Romney was essentially doing the same thing Harry Reid did to him in the 2012 campaign. And it's a topic that will surely come up tonight.

Last night at a forum hosted by Fox News, all four of the other GOP candidates (Trump did not participate) promised to release their tax returns, putting even more pressure on the New York billionaire to do so.

3. Rubio Needs a Knock-Out Punch

Rubio, who is seeking to cement himself as the establishment alternative in the GOP field, needs the performance of his life tonight if he hopes to capture the Republican party’s anti-Trump hopes – a potent force, still, even as the primary season gets later than it seems.

Rubio telegraphed some punches Wednesday after arriving in Texas, hitting Trump as someone who “isn’t a conservative” and for being too close to President Obama on health care and Israel.

4. Texas Two-Step

The debate is being held in Texas, the state Ted Cruz represents in the Senate and that he knows he must win. It's not just his home state, but a delegate bounty, too.

“Super Tuesday I am convinced will be the most important day of the entire presidential cycle,” Cruz said while campaigning in the state yesterday. “There are more delegates awarded on Super Tuesday than any day in the year -- nearly 600, nearly half what is required to win the Republican nomination -- and the crown jewel of Super Tuesday is the great state of Texas."

But because Cruz has the home-field advantage tonight, the pressure will be on for a commanding performance.

5. Stayin’ Alive

John Kasich and Ben Carson will be on stage tonight, but they won’t be the focal points. For the two of them, the challenge will be staying in the game.

Just yesterday, Kasich vowed he wasn’t going anywhere: “I’m going to stay in for a long time,” he said. “I’m going all the way.”

But Carson, in an e-mail message to supporters, started to sound realistic about his campaign’s chances.

Of the dozen states that will be voting on Super Tuesday, Carson wrote, “They are states where I should be very competitive; states like Georgia, Tennessee and Alabama. Without a strong showing, it's going to be very tough for my campaign. That's the honest truth.”

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