Here's the evidence of battery against top Trump aide

The arrest of Corey Lewandowski, campaign manager for Donald Trump, on charges of misdemeanor battery against a female reporter accelerates the downward spiral that the Trump campaign has suffered in recent days. The fact that Trump and his campaign still strongly defend Lewandowski, despite clear video of his involvement, only compounds its impact.

Not that Trump has any real choice. Backing down at this point would make him appear weak to his followers, and they will forgive him every mistake except that one. But to everyone outside Trump's camp, his refusal to apologize or even acknowledge what happened also makes him look weak, and strengthens the growing sense of a campaign coming unraveled.

To be clear, this is not a case of punches being thrown or felony assault.  The security videotape clearly shows Lewandowski walking behind the reporter, Michelle Fields, then reaching out and grabbing Field's arm and yanking her backward as if she were a runaway child so that he can move ahead of her in Trump's wake.

It's an assertion of physical dominance that Lewandowski probably would not have attempted against a man his own size, and probably could not have achieved without risking a confrontation. But because Fields is a physically smaller, weaker person, he apparently felt free to do so. (Afterward, he denied ever laying on finger on Fields, calling her "totally delusional". Just another one of those crazy chicks, in other words.)

Male supporters of Trump who might be tempted to dismiss the situation should ask themselves how they would react if someone treated their wife, sister or mother that way, grabbing her so roughly as to leave bruises on her arm. They might also ask themselves how they themselves would feel if somebody considerably larger and stronger, say a man who is six feet eight and 280 pounds, suddenly grabbed their arm and treated them that way.

The incident can best be understood through a series of four still photos captured from the security video:

Again, this is not a brutal mugging. But it certainly is an act of physical, unprovoked aggression that should not be tolerated. A judge or jury will have the final say, but a charge of misdemeanor battery seems perfectly appropriate.

At the very least, Lewandowski should publicly apologize for his behavior, and Trump should apologize as well for the aspersions that he has cast on Fields' character and veracity in the aftermath. But we all know that's not going to happen. That would require a modicum of class and a capacity to feel shame, and Trump is capable of neither.

Any doubt about that fact was eliminated in a Trump press conference this afternoon. "How do you know those bruises weren't there before?", he asked in defending Lewandowski.