The immediate and universally acclaimed conventional wisdom of the pundit class, summed up here by Mark Halperin, is that Colin Powell's endorsement of Obama is "crushing news" for John McCain.

It's certainly true that getting an endorsement is better than not getting it, but I've never been a believer that endorsements of any kind matter much at all in the end. However, because this race is in large part a referendum on Barack Obama and whether a majority of the country is comfortable with him given his lack of experience, past associations, etc., then perhaps Colin Powell's strong endorsement will help move a few persuadables and/or undecideds into Obama's column.

But my sense is that if a voter is still undecided at this point in the race, they probably won't make up their minds until the final weekend - or even the final day - and it's unlikely that that decision is ultimately going to be influenced by what Colin Powell said on Meet the Press on Sunday.

UPDATE: Mike Murphy says he is "not normally of the view that endorsements mean much in Presidential politics" but calls the Powell endorsement a "real sledgehammer blow" to the McCain campaign. Murphy concludes: "As a great McCain admirer, I am sad to say it, but the truth is the video of Powell's endorsement will boil across You Tube and do great damage in these closing days of the campaign."