Externalities.

That’s what the media pros in the political big leagues call events and forces beyond their control.

And for all the careful scripting, prepackaging, word-smithing, image-shaping, and gesture choreography apparent here at the DNC — exerted in a rigidly disciplined manner over every speaker, every delegate, every sign, every ‘message’ and literally every aspect of the confab — that’s what will determine the forthcoming election.

Despite the record-setting amounts of money both parties have already raised and spent, mostly on television and radio advertising (a combined total of about two million dollars a week was recently being shoveled out the door to local broadcasters and cable networks) and despite the near-maniacal exercises in control being exerted by the Kerry camp here in Boston (and soon to be exerted by the Bush forces in Manhattan), nasty and rude “externalities” are about to intrude.

But first comes tonight’s coronation.

To no one’s surprise, the conventional run up has thus far been without surprises. Modern campaigning has become so much less of an art and more of a science over the past few decades that it’s now been reduced to formula.

Think paint-by-numbers, connect-the dots . . . one reason the networks have decided largely to skip the proceedings, despite millions of viewers who are seeking coverage — and finding it on PBS and cable.

Think, in the poet Ed Dorn’s phrase, of the “kiwanis enthusiasm” emanating from the convention floor.

Think, as Republican Senator Mitch McConnell complained, of the disguised attacks on Bush that are “vile with a smile,” or, as Kerry spokeswoman Stephanie Cutter spun it, think instead if you prefer of the art of “drawing contrasts without drawing blood.”

Think, if only for a moment, of the of the Al Jazeera skybox sign that threatened to spoil the Party’s party and ‘mysteriously’ disappeared…

Think, finally, of the simple fact that the entire text of the Pledge of Allegiance is carefully displayed on the teleprompter so as to ensure that no Democrat will choke at the podium, forget the words, and throw a lifesaver to the flagging Bush campaign!

So John Edwards — a wonderfully fervent stump speaker whose seeming spontaneity on the primary campaign trail allowed him to connect on a visceral level with crowds of voters, and almost led to his snatching the nomination from John Kerry — instead gave a flat, hollowed-out version of his stump speech last night. Not that Edwards was bad — the speech, while not a home run, was still a solid double or triple — but his overriding concern was simply not to make a mistake.

Think damage control. Think how even the ‘red meat’ speeches that preceded Edwards on earlier days, from the likes of Ted Kennedy and Howard Dean, “wrapped invective in a veil of misdirection,” as Todd Purdum put it in the Times today.

So it was left to Al Sharpton, who is probably constitutionally incapable of speaking from a written text, to jazz up the audience by throwing out his script and riffing and rapping like a master.

But even an ‘out of control’ and ‘unscripted’ Sharpton was no doubt part of the overall script, and the Kerry Camp was happy enough to posit Al as the exception that merely proves the rule.

Tonight there will be more of the same. Every step John Kerry takes, every move he makes, every image in the Spielberg-assisted film biography/hagiography that will tell the story of his life in nine-and-a-half moving minutes, all will be carefully staged until the coronation is complete.

Then, after the Packaging Police in the Convention Control Room can no longer shape our every perception, those events and forces beyond the humid confines of the fetid Fleet Center will start to kick in.

Instead of Obama, think Osama . . . Iraq . . . terror on the trains . . . the economy, stupid . . . airplanes that might pierce a crystal blue sky to shatter our buildings and lives at virtually any moment and betray our illusions — our mass hallucination — that we, that anyone, is really in control.

Externalities.