President Obama wants this to be his extreme make-over debate where everything changes.
Governor Romney would like an extreme do-over debate where nothing changes from the first one.
Here are some do's and don'ts to help them both get where they want to go.
Barack Obama won the White House promising hope and change. To win re-election, tonight he has to change everything he did in the first debate and hope voters are convinced.
The president has a way of telling people what they should believe. Tonight, he should ask Americans to support his positions with a better explanation than "it's the right thing to do."
In the first debate, Romney was poised, personable and moderate. In the second debate, he should do it again.
Jujitsu is a way of fighting that turns the strength of an opponent into a weakness. Tonight, the president will be on the attack, and Romney must be ready to deflect, and re-direct, all the criticism.
What the president and the governor don't do tonight will be as important as what they do.
Here are some of the traps they don't want to be caught in:
Less than a month before the election, we still don't know what the president's plans are for a second term. Tonight, he should tell us and not duck or blame George Bush.
Whatever you thought of Joe Biden's performance in the vice-presidential debate, the president does not want to repeat it. Biden was speaking to the democratic base; Obama must speak to America.
Like the president, Mitt Romney has avoided the details of what he'd do if elected. Now's the time to fill in the blanks by being much more specific.
And, most important, do not expect a rerun of the first debate. Bring in a new playbook, and prepare for an energized, engaged, very different president.
In sports, it's playoff time, and many teams face a game they must "win or go home."
Tonight, President Obama is in that position, but with a twist: if he doesn't win, he may have to leave his home in January.