The biggest knock against McCain from the first presidential debate was that he refused to look at or even acknowledge Obama’s presence on the stage and appeared as the stereotypical grumpy old man, raising hackles about a younger generation and generally lacking charm.

The biggest key to McCain’s performance in tonight’s debate is if he can manage to tweak his stage persona and offer a more optimistic alternative to Obama. Problem is, there are no indications that McCain will return to the happy warrior of campaigns gone by (like, say, the GOP primary).

From Politico…

When Politico’s Ryan Grim approached Sen. John McCain (R-Ariz.) after the evening of the Senate bailout vote, the reporter didn’t even get his question out.

“Excuse me, you’re bothering me,� McCain said.

It was a surprising rebuke from a politician who once was famous for palling around with reporters, and who was so media-friendly that he was sometimes known as “the senator from ‘Meet the Press.’�

But what friends call “grumpy McCain� is showing up regularly on the campaign trail, and several top advisers worry that it’s hurting his campaign by making him appear peevish and hunkered down when the country is looking for a larger and more optimistic brand of leadership.

After his first debate with Sen. Barack Obama (D-Ill.), both spectators in the hall and commentators on TV noted that McCain had deliberately avoided looking at his rival.

A close McCain friend said the reason is clear: McCain is miserable about having to run a campaign that’s antithetical to his persona.

“He is basically having to be somebody that he isn’t,� said the friend, who remains strongly supportive. “He is just not a guy that goes on the attack in public. For him to be on the attack constantly, attacking Obama’s character … McCain is uncomfortable with that, and it’s made him grumpy.�