The President got elected largely on his ability to transcend the racial politics of the past. He presented himself as a post-partisan healer who rejected the transparent race-baiting of a Jesse Jackson or an Al Sharpton. It was one of the reasons why the Obama campaign went to such lengths to bury Obama’s association with the viciously racist Rev. Jeremiah Wright—because it undercut the narrative they wanted to portray.

Now, Obama has waded right back into the politics of racial polarization with his attack on a veteran Cambridge police officer.

All this will do is polarize the country. The police officer can hardly be accused of being a racist—he taught classes on stopping racial profiling, tried to save the life of NBA star Reggie Jackson, and has a sterling record on the police force. Yet the President, without knowing all the facts, accused him of “acting stupidly” and insinuated that race played a factor in the arrest.

Based on the police report of the incident, race did play a part. Prof. Gates’ racist diatribe, not his attempting to get into his own house, is what got him arrested. The mere sight of a white police officer legitimately trying to do his job was met by a tirade by Gates. If anything, it was Gates who “acted stupidly.” Perhaps not stupidly enough to get arrested, but stupidly enough that he was hardly a victim in all this.

By taking sides in this matter, the President was walked right back into the fields of racial polarization. He has diminished his office by attacking a law enforcement officer without knowing the facts—and even if Sgt. Crowley was at fault, the President should not have injected himself into the matter in the first place.

This may not sink the Obama Presidency, but it does hurt him. He came into the Oval Office with the noble goal of being a President for both Black America and White America, a President that would try to heal racial divisions. Now, he has helped to open another racial wound in this country. He “acted stupidly” in doing so, and it may well end up costing him politically at a time when he’s already starting to take political heat.