We wrote a long post a few days back, trying to put the rest a perennial misperception: that Obama lacks the ability to be aggressive, when aggression is called for. But for those who absolutely must have some punch with their political cookies, you’ll savor CQ’s portrait of the Senate during last night’s bailout vote. Obama and McCain were both on hand, which, given that McCain hasn’t made a vote in over four months, was intriguing in and of itself.

And Obama did what he tends to do on the floor of the Senate: he walks over to the last person to diss him on the campaign trail, and he stretches out his hand.

Sure, it’s a social nicety; sure, it’s designed to show the C-Span camera that he can rise above any personal bickering.

But it’s also very in your face. Or in McCain’s face, rather.

And in this case, McCain responded as we’ve come to expect: no eye contact, clenched jaw, instinctively reaching for the pepper spray in the pocket of his blazer.

We’ll post the video later in the day, once it becomes available, but almost certainly the nuance will be lost. Added bonus to David Nather’s blog account: McCain was chatting with Mel Martinez and guess who on the GOP side?

That’s right: Big Joe Lieberman.

You’ll remember that Obama worked this same handshake/buttkick routine on Lieberman a few months back, after the Senator from Connecticut auditioned as attack dog for McCain. In that little confrontation, Obama walked Lieberman to the back of the chamber for their private chat. (Brilliant video here.)

Now here’s the thing: grown men, Senators who want to be President, should be able to exchange a smile and a handshake with an opponent in a formal setting like the Senate. Those who can’t (google Cheney, Dick, F-Bomb, for instance) shouldn’t be trusted with the office.

And clearly Obama is staging this particular social test to demonstrate that he can pass it.

But there’s a little more to it. The Senate is one of the most tradition-bound systems in America; it’s also run entirely on the seniority system. For those who thought that Bernie Sanders would run amok once he moved up from the House, there’s been a few years of realization: even Bernie is stymied by a set of rules always favoring years in office.

You can’t get a muffin in the Senate cafeteria until you’ve been there a decade.

John McCain did his apprenticeship under those rules. Now, after a quarter century in the institution, he’s a Senior Senator. It’s All Him. And then he looks up, and here comes the Junior Senator from Illinois, with all of four years under his belt, making a casual social power play on the floor of the Senate itself. The handshake must seem like an open insult.

And this audacity, on top of polls showing Palin a drag on the ticket, on top of a first debate that ended somehow with Obama winning on foreign policy, is slowly driving McCain insane.

If you missed McCain’s interview yesterday with the Des Moines Register, you won’t understand exactly what we mean. Take a look. This is a man who feels that now, after a lifetime of reaching for it, a career of being told that his story uniquely qualifies him to hold the Oval Office, the Presidency is not slipping from his grasp but being stolen from him.

By Obama, by the media, by Liberals, by guys at cheese-steak stands who shout out trapdoor questions about Pakistan.

And he’s really angry about it. That’s what happens to Republican hopefuls when they go down, because it happens so rarely that they take it personally: they blow their stacks, publicly.

Think George H. W. Bush in the final days, ranting about “Ozone Man,” calling Clinton a “Bozo.” Think Bob Dole, who simply couldn’t understand why Bob Dole couldn’t be President, why Americans wouldn’t vote for Bob Dole (”Where’s the outrage?”).

And you have to believe that whoever’s standing next to McCain when he finally blows is going to take one hell of a roundhouse to the jaw.

We can only pray it’s Lieberman.