"trouble makers" that are actually the problem.  I doubt that most Republicans are strategically voting based upon who they think would be easier to run against but rather who they think would be the lesser of two Democratic evils.

It's true that they may support McCain in the fall, and that is cause for concern that counteracts that rush of excitement.

Of course, what I'm hoping is that, even if existing voters aren't shifting more Democratic, that emerging young voters are significantly more Democratic than Republican, because that's the way that values change over time...generational change.  Most people stick with their political leanings throughout life, so more support from the younger generations has a more powerful long term effect.