Libertarians had a pretty good 2012 election cycle. Presidential nominee Gary Johnson got the highest vote total ever by a Libertarian White House candidate. Now Libertarians can plausibly claim to be the deciding factors in races won by major party candidates.
Daily Kos Elections reports that Libertarians may have provided the winning margin for Democrats in at least nine congressional and gubernatorial elections. Take Democratic Rep. Joe Donnelly's upset for Indiana Senate over Republican Richard Mourdock. Libertarian candidate Andy Horning garnered 146,453 votes, while Donnelly beat his GOP rival by 141,575 votes.