Mesa, Arizona (CNN) -- Finality can be a driving force in critical decision making, and it goes without saying that tonight's presidential debate is weighing heavily on the minds of the four Republican presidential candidates.
It's the final debate before next week's critical Arizona and Michigan primaries.
It's the final debate before Super Tuesday, when voters in 10 states on March 6 express their preference on who should carry the GOP flag into November.
And it might be the last time Newt Gingrich, Ron Paul, Mitt Romney and Rick Santorum appear on the same stage.
So much at stake, so little time.
The 90-minute discussion will offer these four GOP hopefuls one last chance to speak to a national audience and try to differentiate themselves from one another.
As we have witnessed so far in this political roller coaster ride, a game-changing moment can shake up this race ... one more time.
And with that, here are five things to look for in tonight's debate, with an acknowledgment and hope -- after all, surprises are what makes life interesting -- there will be five more.
1. Gingrich has been the master in the art of debating, a skill that has helped him revive a campaign left for dead last summer. That's except when Romney knocked him on his back in last month's CNN debate in Florida. The former House speaker was so angry at Romney he made these charges and this promise:
"I've never had a person stand next to me in a civil engagement and be as substantially dishonest as he was. I mean go look at what he said. You have Larry Sabato in the middle of the debate tweeting that Romney was being factually false. Now I didn't have any good mechanisms; I will by the next debate.
"I didn't have any good mechanisms to turn to somebody who was being blatantly dishonest to the entire country as a candidate to the president. If you can't tell the truth as a candidate for the president, which is by the way a charge that has been made by McCain, by Fred Thompson, by Huckabee."
Keep an eye on Gingrich. What does he mean by "mechanism"? We can only wait to see what he has up his sleeve.
2. Santorum has largely stood in the shadows for the previous 19 debates ... until now.
The white-hot spotlight is now shining brightly on the former Pennsylvania senator as national polls have thrust him into the pole position. Santorum thrives as the hunter; can he handle being hunted? This debate is much about how Santorum handles the heat as it is about how Gingrich and Romney perform
No, I am not saying Herman Cain's economic plan will become a major topic of the debate. But Cain has proven that a slogan can put wind in your sails. Gingrich is talking energy; Romney the economy, Santorum social issues and Paul ... well, he never really wavers from the national debt and distrust of the Federal Reserve.
What will be the slogan that pops tonight? What message will echo beyond the Mesa city limits and be remembered tomorrow?
4. Religion, religion, religion.
An underlying discussion throughout this campaign has been Romney's Mormon religion. But not since John F. Kennedy's 1960 speech to the Greater Houston Ministerial Association has Catholicism been thrust into the presidential spotlight.
It is Ash Wednesday -- an important day for Catholics. Santorum and Gingrich have been outspoken about their Catholic faith. Will it become a topic of discussion tonight?
5. This could be the final debate of the GOP primary, giving the candidates one last shot to address one another in person.
Unlike CNN's previous six GOP presidential debates this election cycle, the candidates tonight will be seated at a table.
Will the close proximity to one another dissuade them from attacking one other or will the high stakes result in short fuses and turn a discussion about their respective visions for the future into the equivalent of a political knife fight?
We will get these answers tonight and perhaps more than we expected.