WASHINGTON After two debates, one presidential and one vice presidential, we can fairly conclude that Obama and Biden are happy warriors.

They just smile and smile and smile.

Whereas President Obama’s smile during his debate with Mitt Romney seemed to be an afterthought, proffered as recompense to relieve the strain of his lackluster performance, Vice President Biden’s was an Uzi. From the time he sat down next to Paul Ryan, he was locked and loaded with the pearliest chompers since Matt Dillon donned horse veneers to impress Cameron “There’s Something About Mary” Diaz.

No matter what Ryan said (except when he told a personal story), Biden smiled. Like the Cheshire cat, he smiled. Like an Ultra Brite model, he smiled. Like someone trying to seem friendly, bemused, stunned to hear such malarkey from his debate opponent, fill-in-the-blank, he smiled. But Biden’s was no friendly smile. It looked like one, otherwise known as acting, but it was no more sincere than Biden’s repeated references to Ryan as “my friend.”

It was a tactical weapon intended to intimidate and out-psych his wonky opponent.

Post-debate commentary has included the likelihood that Democrats, deflated since Sub-Obama’s encounter with Uber-Romney, saw Biden as a mirthful wonk-slayer. A Goliath in years and stature, he slew young David from Accounting. Which is, of course, not the way the story is supposed to go.

Non-Democrats, including Republicans and independents, likely saw Biden as dismissive, rude and unnecessarily condescending. A man confident of his facts doesn’t have to deflect a weak argument with a sneer or a smile. A senior statesman can afford to be gracious, especially if he believes the facts are on his side.

But were they? Fact-checkers are furiously whittling away, but one obvious and potentially harmful error was the vice president’s incorrect assertion that our murdered ambassador and staff in Benghazi hadn’t asked for and been denied additional security. In congressional testimony the day before, State Department officials admitted exactly that.

Biden did render a satisfying “gotcha” of his own when he reminded Ryan that the Wisconsin congressman had written the Obama administration two letters requesting stimulus funds. Ouch.

Biden’s smile, though it may be the most remembered part of the debate, probably didn’t work as intended. Democrats may have overlooked the inauthenticity of the smile, not to mention Biden’s repeated interruptions, because he was projecting the aggression they were feeling. As their agent, he was compensating for the president’s perceived weakness. The anger they feel is really toward Obama, of course; Ryan was merely his stand-in.

When Biden and Obama project a sincere smile, it is indeed a sunny day. Obama’s legendary likability most likely is linked to his billion-buck grin.

To receive a warm smile is its own reward. To be on the receiving end of an insincere smile, or one that doesn’t fit the message being delivered, is psychological trickery.

Finally, a politician who smiles while trying to take you down may be a pro, but he’s no friend.

“Who do you trust?” Biden asked Americans as he looked directly into the camera.

Well, now, funny you should ask.