Kristol now says "I regret the error" about Obama

As reported earlier today, Bill Kristol made what Marc Ambinder a "major, prejudicial error" about Obama in his NY Times column today. Kristol has acknowleged -- and regrets -- the error. Kristol should regret the error. Kristol should never have made the error in the first place:

In this column, I cite a report that Sen. Obama had attended services at Trinity Church on July 22, 2007. The Obama campaign has provided information showing that Senator Obama did not attend Trinity that day. I regret the error.

Has Kristol learned that the right wing site, NewsMax, might not be a reliable source? Has the NY Times learned that Kristol isn't reliable?

Update: Newsmax's Kessler Scrubs Reference To His Obama Factual Blunder From His Wiki Page