The idea that the range of acceptability of political views has or is being expanded presently by the efforts of Donald Trump and Bernie Sanders is certainly popular in the media, and even in the general population (whose political expectations have been thrown out of whack by a fast changing information/ communications environment). However, there is very little reason to assume that greater flexibility in political tastes, styles, and preferences as reflected in opinion polls conducted outside of the high intensity closing weeks of an election campaign are or will translate into unprecedented voting behavior sufficient to make this year's unconventional movement candidates electorally viable.
The biggest constraint on voters’ decisions also happens to be a notion given uniformly negative attention and treatment in the news media AND by political actors (candidates, operatives, policy advocates, ideologues, revolutionaries, etc…) More than a half century of voter behavior research shows us that PARTISANSHIP (called “Party Identification” and defined as a psychological attachment to one or the other party) drives voter choices far more than candidate quality, ideological purity, discrete policy preferences, or even media coverage.
The average American registers almost instinctive disgust with “partisanship” when surveyed, yet consciously or unconsciously adheres to long held party-based preferences when they close the curtain at the polls on Election Day. Media treatment of partisanship is almost entirely negative, which makes good sense when you consider that political parties were once the most trusted intermediaries between voters and government/ politics. The parties are natural competitors (though now largely vanquished competitors) with the media for the attention of voters/news consumers. If partisanship explains most election outcomes (which it does), who needs 24/7/365 media coverage and analysis of every foible or gaffe?
This year, on both the left and the right, the media and the candidates are bending over backward to take crowd pleasing, poll-driven, and focused grouped shots at a familiar punching bag, the “Party Establishment,” which is purported to command the blind obedience of unthinking drones, when it’s not being pronounced dead that is. There is a huge gap between media treatment and reported public opinion about partisanship on the one hand and the actual reliance on partisanship by voters when they are choosing candidates at the polls, on the other hand.
Candidates, campaign operatives, high profile donors and endorsers, media analysts, and reporters all have very strong incentives to base their electoral projections primarily on factors that their target audiences both understand and believe credible. Unfortunately, that means willfully discounting the single most potent and predictive factor in election outcomes, party identity. Of course, if campaigners, pollsters, and media pundits took the role of party leanings more seriously, most of them would be out of a job.
One very important reason I can confidently predict the eventual failure of both the Trump and Sanders campaigns is that I am not ignoring the elephant (or the donkey) in the voting booth. The media and campaign narratives being constructed by self-interested actors are decidedly incomplete. The (often passionate) belief that these narratives tell the whole truth combined with the virtually instinctive impulse of Americans to disparage the roles and functions of political parties (i.e. the rest of the story) produces a HUGE blind spot that few so blinded have incentive to confront.
Hillary will win the nomination because Dems and Dem leaners what to win in the fall, the urgency of which is magnified a thousand times by the prospect of total GOP control of the federal government. Revolutions in pursuit of hope and change are compelling and fun, but not compelling enough to risk the repeal of the 20th Century. Trump should also lose (though admittedly things are less clear in the GOP) because Republicans both want to "take back their country" and because many are long time sufferers of Clinton Derangement Syndrome and fear that Hillary Clinton's election would hasten the apocalypse.