Writing in the Washington Post, Dana Milbank discusses the downward trend in President Obama’s approval rating among liberals — a decline that seems likely to accelerate now that he has announced an escalation in what shall henceforward be known as Mr. Obama’s War.  The disillusionment…

… was bound to happen eventually. Obama had become to his youthful supporters a vessel for all of their liberal hopes. They saw him as a transformational figure who would end war, save the Earth from global warming, restore the economy — and still be home for dinner. They lashed out at anybody who dared to suggest that Obama was just another politician, subject to calculation, expediency and vanity like all the rest.

My first substantive post on this blog dealt with this very issue.  But in my case, I welcomed the emerging evidence that Obama is a politician, not a messiah.  I still do.

From that July 2008 post:

My biggest concern with Obama was the very thing that endeared him to many others — the idea that he was “not a politician,” or was “a new kind of politician.” I never believed that to be the case… but enough people believed it that I had to consider the possibility. The idea of a president who is not a politician is scary. It’s like the idea of a Supreme Court justice who’s not a lawyer. There’s no law against it, and it might even work out OK. But it makes no more sense to put a non-politician in the country’s top political job than it would to put a non-lawyer in the top legal job.

It ain’t always pretty and it ain’t always fair, but politics is the mechanism through which our country is governed.  How many times have you heard variants of “So-and-so is just doing that for political reasons,” with the word “political” spat out as a term of contempt.  But another way to say “doing something for political reasons” is “representing one’s constituents.”

As with any politician, Obama’s constituency is far from monolithic.  But he had a large cadre of supporters who bought into the Obamessiah myth, and it was inevitable that they eventually would feel betrayed.  As he positions himself for re-election, his twin goals will be to convince enough of the former true believers that he is still the best option available, while doing what needs to be done to stabilize Afghanistan and defeat the jihadists.

There’s a tension between those two goals, as we can see in the announcement of the new strategy for Mr. Obama’s War.  His ill-advised announcement of a date certain for beginning to reverse the coming surge is a face-saving fig leaf for the true believers.  Fortunately, he’ll have plenty of time between now and July 2011 to figure out how to explain, if necessary, that the withdrawal must be delayed.

But in the meantime, sounding a tentative trumpet is not the way to rally the troops and win a war.