By joining forces with the Green Party's Jill Stein, the Vermont senator would pose a formidable independent challenge to both Donald Trump and Hillary Clinton, two of the major parties' most unpopular candidates in recent history.
The 25 alternative candidates elected to state legislatures in the 2012 election might not seem like a huge groundswell, but it represents the highest level of independent representation in statehouses since 1942.
If you're not a Democrat or a Republican, the widely held belief goes, you have zero chance of winning an election. But there is one state where someone not affiliated with the two major parties has a good shot at winning a seat in the United States: Maine.
As Bill Moyers explores in the latest edition of his program, third parties have a place in the American political system, despite the fact that it's dominated by Democrats and Republicans.