50%
Democrats have their built-in electoral college advantage. Republicans have Trump (high-energy, can motivate the base to go out and vote) and Rubio (can rally the base and gain substantial moderate support.) These balance out fairly well.
Sooner or later, the polls will show that Americans don't want the role of president to be run by criminals, dynasties, or lying politicians. The DNC may soon realize they made a big mistake in rolling out the red carpet to a golden-nomination throne for Clinton without actually giving the party a wide selection of viable, contrasting, and moderate options to choose from. There never was a choice. Although the GOP is a mess, they will be able to select their first home-grown representative in the election in forever. If this nomination season goes as expected, the general election will be between arguably the biggest career politician in existence against an anti-politician outsider. The trends show that there are less people affiliating with either political party. People are tired of playing politics. That may become very apparent in this upcoming general election.
Great summary. Regardless of your own political views, we all know that 2016 seems to be setting up as an anti-establishment election. People are tired of politicians from both sides. Regardless of your own party, you
don't get more politician than Hillary Clinton. It's quite an albatross.