The only real value of endorsements is that they can, under certain circumstances, influence the Washington press corps. I've never once talked to a voter who made their decision directly based on an endorsement, not an endorsement by a newspaper, not an endorsement by an individual. Powell's endorsement of Obama is essentially meaningless except it gives the chattering classes something to chatter about.
To my mind, the more a consummate Washington insider like Colin Powell describes Obama as "transformational," the less likely it is that he actually is transformational. These folks have been made rich and famous by the system as it is, and the last thing they want is to see that system changed. Their real complaint about Bush, in fact, is that, through arrant incompetence, he's set up conditions whereby average people might, themselves, "endorse" a truly transformational figure by voting for him. If Obama were that guy, there is no way Powell, or the Post, or any other establishment voice, would be endorsing him. They want someone who will take us back to 2000, when people were content like sheep, when the established order wasn't shaking, when their position (with its money and influence) was secure, when the word "transformation" could only have negative connotations, because who would want to change something that worked so well? This was a status quo that ensured Colin Powell's children got soft jobs in government, followed by softer jobs on boards of directors, ensured that Luke Russert would follow in the lucrative footsteps of Tim. Transforming those circumstances they want no part of, and to judge by the number and kind of endorsements Obama is getting, they feel confident he won't be doing it. And yet those very circumstances led us to where we are.
Powell does nail a lot of the tactical stuff:
But the problems we have go further than McCain's sleazy campaign.