Well, that didn't take long.
After arresting Harvard Professor Henry Louis Gates for disorderly conduct when he loudly protested police activity at his own home, the State of Massachusetts today dropped all charges against him.
The arrest arose out of a report that two black males with backpacks were apparently attempting to force their way into a residence. In fact, Gates, a distinguished African-American scholar, had just returned home from China to discover his front door had been damaged. Apparently, the person who called police had observed Gates forcing his way into his own home. (The report that there were two black males involved remains unexplained.)
When police arrived, Gates was in his house, on the telephone to the management company for his property. As of yesterday, article about the arrest included a link to the police reports describing the basis for the arrest. The link no longer exists, doubtless as a result of the termination of the prosecution of Professor Gates. To the best of my memory, however, the police reported that Gates was angered by the police presence; that he showed police identification establishing that he was in his own residence; that Gates was angered by what he perceived to be a refusal by the officers to identify themselves by name or badge number; that as the police left his house, Gates followed and continued to yell at them from his front porch; and that bystanders "appeared alarmed" because of what was happening.
It's hard to tell from the news article, but it would appear that part of the agreement between Gates and the Commonwealth of Massachusetts was that Gates would not sue or that he stipulated to probable cause for the arrest (which would have the same effect). If so, he's a better man than I. Under Massachusetts law, "disorderly conduct" does not include protected First Amendment speech nor does it cover the means chosen to deliver such speech. (The statute is discussed here. I apologize that I can't find a better citation for it right now, but the discussion in that case should make clear that Gates's behavior was indeed constitutionally protected.) There was, accordingly, no probable cause for the arrest. Most likely, both Gates and the Commonwealth decided to put the whole incident behind them and attribute any misbehavior on either side to the fact that all involved seem to have had a bad day.