“I’m a pretty friendly guy,” President Obama said near the end of his White House news conference Monday afternoon.

The claim might have been a touch more plausible if he hadn’t spent the bulk of the previous hour demonstrating just how adversarial he could be. Indeed, there was no precipitating event that led him to schedule the last-minute session in the East Room — lending credibility to the theory that he summoned reporters so he could bait Republicans.

“If congressional Republicans refuse to pay America’s bills on time, Social Security checks and veterans’ benefits will be delayed,” the friendly president said, explaining his refusal to negotiate over increasing the debt limit.

Calling the opposition’s stance “absurd,” Obama advised Republicans that they “have two choices here: They can act responsibly, and pay America’s bills; or they can act irresponsibly, and put America through another economic crisis. But they will not collect a ransom in exchange for not crashing the American economy . . . And they better choose quickly, because time is running short.”

And that was just the opening statement. The hectoring continued through the Q&A. Exactly one month after the massacre at an elementary school in Newtown, Conn., Obama said of debt-reduction talks: “What I will not do is to have that negotiation with a gun at the head of the American people.”

The Republicans’ view, President Congeniality added, “was rejected by the American people when it was debated during the presidential campaign . . . But if the House Republicans disagree with that and they want to shut down the government to see if they can get their way on it, that’s their prerogative.”

Arguably, Obama’s no-more-Mr.-Nice-Guy approach is good politics. His first-term experience made clear that he gained nothing from Republicans when he took a passive approach. When it comes to getting things done in Washington, there’s no substitute for forceful presidential leadership. Teddy Roosevelt, whose oil-on-canvas likeness gazed at Obama from an East Room wall, probably would have approved.

Yet the performance was also a reminder of why Obama isn’t noted for his interpersonal warmth — a topic Jackie Calmes of the New York Times asked him to address when she mentioned the criticism that he and his staff are insular and that he doesn’t socialize.

It’s tempting to wonder whether Obama could achieve more if he could establish personal connections with Republicans on Capitol Hill. But Obama disparaged the notion behind Calmes’ question — that a better bedside manner could help his agenda.

“I like a good party,” the president informed her after attesting to his “friendly guy” status. “Really what’s gone on in terms of some of the paralysis here in Washington, or difficulties in negotiations, just have to do with some very stark differences in terms of policy.”

That may be true, but until recent years, sharp disagreements were smoothed by personal ties. On Monday, by contrast, Obama showed unrelenting hostility toward the opposition, accompanying his remarks with dismissive shrugs and skeptical frowns.