Rather ask: Will Bernie Sanders win the nomination?
That's a much harder question to answer, less because of the fickle electorate and more because of the forces of traditional power arrayed against Sanders. His bottom-up campaign looks all the more impressive when you look at how the very party he is running for is determined not to have him.
By April 2015, over half of the Democratic Senate caucus had already backed [Hillary Clinton's] bid for the nomination — far more early endorsements than any candidate in either party has gained in this century. To date Clinton has won the backing of 38 of 46 Senate Democrats, 148 of 188 House Democrats, and 12 of 18 Democratic governors.
In contrast, Sanders has two House Reps and many many many people whose only influence is the ballot. If he can win against his own party he's certainly passed the ever crooked "electable" test so often used to weed out dissident voices, so why would a Democratic Party that actually wants to hold on to the White House still oppose him?
It's not his foreign policy - the biggest point of criticism among his Leftist detractors. Which do indeed exist. While not voting for the Iraq War, Sanders is just as pro-Israel and pro-Empire as every other D on Capitol Hill. This would do nothing to hurt his "electability" either as rank and file Democrats - whatever their protestations in the latter half of the Bush II presidency - are just as eager for war as the Republicans they post snarky memes about on Facebook. War may be bad for children and other living things but plenty of American liberals can find a way to rationalize it as long as one of their own pulls the trigger.
Just look at that Kenyan Islamo-Socialist, Barack Obama. Mister Hope and Change may prefer drone warfare to boots on the ground, but the results are much the same. Drones make good cold, imperialist logic but it's still a far cry from the radical peace based foreign policy advocated by Kucinich in 2008 and the Green Party today.
And as gross as it may sound, being a peacenik really would make Sanders unelectable. The Cruise Missile Liberals want America to kick ass just as much as the muzzie-hating conservatives, they just want it done humanely - as if humane war is even possible! - and their rhetoric isn't as obviously racist. These two factions have never been as opposed as the culture war noise would have you suspect, as they've always been little more than feuding sides of the same white middle class family.
It's not his conventional foreign policy that has the party brass so scared, but rather Sanders's economic priorities. He calls himself a democratic socialist but his proposals are little more than reheated New Deal policies. That's still too far to the left for history's second biggest fans of capitalism, whether out of fear of change or because it would drive away the corporate money that post-Clinton Democrats use to win elections. That they haven't done anything very liberal since the New Deal doesn't stop people from arguing about the importance of their winning elections.
Which gets to the very heart of opposition to Sanders: He challenges the fundamental assumptions of American elections. His economic populism has already crossed the usual Red versus Blue divide, uniting working whites with urban people of color. That's something very new and very frightening to a party that thought it could run on the fear that a Republican would overturn Roe V. Wade indefinitely, much as Karl Rove thought the GOP could run on the false promise of doing just that.
Sanders, like Occupy, has re-oriented the political dialogue to the basic needs of the citizenry - prompting Hillary Clinton and her daughter to disparage any notion of universal healthcare with rhetoric straight out of Mit Romney's campaign. That blue collar Christians, atheist vegan programmers, and black nurses all think it's a good idea doesn't matter because there is no business support for such an unprofitable venture.
And this is what Election 2016 comes down to. A test not just of the Democratic Party but of American democracy in general. If a popularly supported insurgent candidate like Sanders is defeated by money and privilege, what chance do the rest of us little people really have?