It's clear that the two-party system has its disadvantages. Politics aside, I'm sure both major American parties have often wished for an alternative option. Particularly as it relates to a guy whose name rhymes with Tronald Dump.
Voting third party, especially as a liberally-minded person, is (probably correctly) seen as hurting the odds for the Democrat. The two-party system doesn't leave a lot of room for an underdog, regardless of their popularity.
The fix: we adopt the Kickstarter system. Voters are given first and second choices on a ballot. Candidates need to pass a certain threshold in order to get any votes. If that threshold isn't surpassed, they get nothing. They lose. Good day sir.
As it turns out, this isn't a new idea (dammit)! Instant Runoff Voting is already used in Australia, India and Ireland, to name a few.
Lazily quoting Wikipedia:
The spoiler effect is when a difference is made to the anticipated outcome of an election due to the presence on the ballot paper of a candidate who [predictably] will lose. Most often this is when two or more politically similar candidates divide the vote for the more popular end of the political spectrum. That is, each receives fewer votes than a single opponent on the unpopular end of the spectrum who is disliked by the majority of voters but who wins from the advantage that, on that unpopular side, he or she is unopposed.
Proponents of IRV note that by reducing the spoiler effect, IRV makes it safe to vote honestly for marginal parties, and so discourages tactical voting: under a plurality system, voters who sympathize most strongly with a marginal candidate are strongly encouraged to instead vote for a more popular candidate who shares some of the same principles, since that candidate has a much greater chance of being elected and a vote for the marginal candidate will not result the marginal candidate's election.
Of course, this ignores other issues, like ballot complexity. As noted by electology.org, it's much simpler to allow a voter to select multiple candidates on a ballot.
The resulting algorithm ends up being easier to run as well. You simply tally up the candidate with the most votes. Not that we haven't had problems with that.