I don't always like how Rand plays the game, and I don't see how voting as he did had any political benefit with respect to future elections (at the very least, I would have abstained). However, a single "no" vote would have accomplished nothing more than making a statement. I LOVE when Ron does this, because statements need to be made, and I greatly prefer his open defiance to Rand's shrewd calculations...but it's quite possible that Rand views principles slightly differently from some of us, in that he only feels that he'd be compromising his principles if his vote may actually affect the outcome. If so, I don't think that picking his battles in that way necessarily makes him less principled, and it gives him latitude to spread the liberty message from another angle:
Whereas Ron takes every opportunity to drastically reshape the discussion and preach the gospel from the rooftops to an audience that often doesn't care to listen, Rand seems to be much more subtle in the way he approaches things. It's quite possible that Rand may have seen an intangible benefit in this vote that many of us don't; for instance, he has been working hard to persuade his Republican colleagues to take baby steps in his (and Ron's, and our) direction. Voting no couldn't have hindered this legislation in any way, but voting as he did might be a way to keep communication lanes open with colleagues who are overly paranoid about Iran. His efforts to move the other Senators in his direction may be futile, or they may bear fruit some years down the road. It's still too early to tell, but in the extreme case, Rand's consistent dialogue with the other Republican Senators may eventually mean the difference between coming back from the edge or plunging into complete tyranny. It's dirty business, and it's risky business, and Ron's approach definitely speaks to me more...but I can recognize and appreciate what Rand seems to be attempting, and for all I know it might help save this country someday. Given a choice between their approaches, I'd pick Ron's every day, but I'd like to think they're complementary in the end.
Ultimately, I'm disappointed in Rand's vote, but considering a "no" vote would have accomplished nothing, I'd much rather withhold judgment, give him the benefit of the doubt, and let his other efforts justify my patience.