A visual explanation of one of the methods of Ranked Choice/Preferential voting! I love it. This video from FairVote.org makes a very good point for Dem and GOP supporters: Instant Runoff Voting would limit the effect of spoiler candidates.
If you are committed to staying with the Republican Party (as many of my friends are), watch the video, but consider Candidate 'A' to a Democrat, 'B' Republican, and 'C' Constitution Party (a conservative third party) as you watch.
Big party supporters might want to be considering this as well. According to the video, spoiler candidates today can have an even greater effect at a local level than they do on a national scale. Every politician starts somewhere, and many (most?) start in local elections. Most don't Schwarzenegger their way into a governorship. Remember how far Sarah Palin has come? Wasilla was a necessary step before her eventual Vice Presidential candidacy. Most major candidates have a longer journey before reaching that stage, though. Again, I re-iterate the Chinese axiom: "the journey of a thousand miles begins with one step."
Perhaps my biggest reason to support Ranked Choice Voting is that I believe it would be a game changer for the political arena. Political parties would eventually be forced to court voters as independent candidates begin to claim seats as mayors, state legislators, and so on. I would be concerned, however, if it spawned a mess of flip-floppy mercenary candidates ready to run for whatever party will have them when they don't get the GOP nomination.
Last thought: I, for one, helped vote G.W. Bush into a second term on an "anybody but John Kerry" platform in 2004. I KNOW I'm not alone. I don't regret it, but I wish I'd had another choice.