Are Clintonistas Trying Sabatoge of Dems in 2008?

I just saw this article in which Sid Blumenthal alleges that McCain plotted to leave the Republicans and caucus with the Democrats a few years ago.  What is Blumenthal's motivation here?

Even if this is 100% true, isn't this actually bad for a Democrat to publicize this?  After all, the Democrat strategy against McCain will be to try to turn the election into a referendum on Bush and present McCain as Bush's third term.

I just saw this article in which Sid Blumenthal alleges that McCain plotted to leave the Republicans and caucus with the Democrats a few years ago.  What is Blumenthal's motivation here?

Even if this is 100% true, isn't this actually bad for a Democrat to publicize this?  After all, the Democrat strategy against McCain will be to try to turn the election into a referendum on Bush and present McCain as Bush's third term. Blumenthal undercut that effort.  While true political junkies know that McCain and Bush haven't been best friends, and McCain has made a hobby of insulting his party's base, most observers won't be that astute.  Blumenthal bull-horning this information reassures skeptical independents - whom McCain has always done well with - that McCain is in fact a different type of Republican.  While the revelation may make for some uncomfortable moments with the conservative base for McCain, it won't really hurt him.  As Blumenthal said, the Republicans are historically more disciplined than the Dems, and they are mature enough to know that accomplishing their objectives will be easier with a McCain Presidency than an Obama one.

The obvious thought is that the Clinton's know that winning in 2008 is nearly impossible - they can't get the nod.  They also know that Hillary won't get tapped as the nominee since she brings little to value to the ticket in a general election campaign.  If Obama wins, that puts her out until the next open primary in 2016, at which time Clinton will be nearly 70 years old.  Plus, Obama will most likely have a VP who will have his/her eye on the top job and will be in a much stronger position to get it (unless Obama goes with an older, experienced hand like Bush did in 2000, which would not be a bad strategy for Obama to follow in all actuality).  So, Clinton knows this is do or die.  

Now, maybe I am reading too much into this.  Blumenthal is trying to sell a book after all (he made these remarks at a book signing).  But, there is no more rabid a Clintonista than Blumenthal, and he is a smart guy who understands the political ramifications of every thing he does.  Occam's razor states look for the simplest solution, which would probably mean he was popping off trying to sell some books.  Clintonista's razor states look for the most selfish solution.  Which one applies here?