There are only 2 reasons 3rd parties have a difficult time being successful in America today.

1. The 2-party monopoly has successfully usurped the legal system, for example the anti-American McCain-Feingold and it's 300+ pages of rules and regulations, in order to lock-out (financially and legally) any efforts to un-seat them.

2.  The will of the people.  Or, what I really mean to say is - the lack of will in Americans today to put their foot down.

McCain lost Michigan by a large margin.  Voting for politicians is also no different than "voting with your dollars" at your favorite store.  So you tell me ...

If people like myself, feel the RNC has gone too progressive, or at best, Democrat-lite, what would give us the better opportunity in the future, of getting a Republican candidate we actually like?

a. voting for McCain.
b. voting for Libertarian candidate Bob Barr.

Again, McCain lost by a wide margin.  In other words, he didn't have a (reasonable) chance!  So, voting for McCain out of "loyalty" or because "we only have 2 choices" would have sent the RNC what message?  Support more progressives!

Voting for Barr on the other hand, would send what message to the RNC?  Back geniunely conservative candidates, or you're soon to be out of business!