Many Democrats, understandably fearing a Trump victory, want Sanders to leave the race, but that would be an historic mistake. America needs an ongoing, continuous radical movement of the sort that Sanders represents; if he pulls out now, all of the energy and consciousness-raising that he has generated would be lost.
Clinton supporters have not understood Sanders' game plan. Of course, he sought the Presidency, but even more importantly, he has a long view. He wants to change the Democratic Party so that the kinds of things he stands for-- health care as a right; universally available high education; a rational foreign policy, instead of the US being "the indispensable nation"-- can continue to be fought for. The Presidency is very important but it doesn't trump (pun intended) building a continuing radical movement inside and outside of the Democratic Party.
Neo-liberal politics, given its American shape by Bill Clinton, and perpetuated by Obama, is premised on the idea that America does not need a Left. Technocratic management of the economy, expansion of "credit" in such forms as student loans, identity politics, meritocratic feminism, and caution in pursuing global power is sufficient. In this view the purpose of a figure like Sanders is to "push" the mainstream candidate to the left, but then to go home.
Consider what happened in 2008, when a vast movement arose to support Barack Obama. When Obama became President he basically told that movement, "thank you very much, I'll take it from here." As a result, his Presidency was weakened from the very beginning, and the Republicans blocked much that could have been accomplished.
Consider, too, the experience of "Occupy Wall Street," one of the great moments in the history of the American Left. Occupy Wall Street changed the nature of political discussion in America, bringing the question of inequality to the fore. It supplied Obama with some semblance of a new direction in the 2012 Election. But Occupy Wall Street dissipated and inequality today is much greater than it was in 2011. OWS needed to become a part of a continuing movement, as does the Sanders campaign today.
There have been creative interchanges between American Presidents and the Left. Lincoln and the abolitionists cooperated during the Civil War, even though Lincoln believed in racial inequality, which the more radical abolitionists rejected. Similarly Roosevelt cooperated with radical labor leaders, and even Communists during the New Deal. It is highly unlikely that Hillary, who unlike Lincoln and FDR, is a completely conventional person, will develop such a relationship with a Left, but the only chance we have of this happening is if Sanders sticks around and poses a challenge to her.
There are times in history when politics needs to be put aside and the nation has to rally around a single cause. The typical example of this is a time of foreign invasion, in other words a national emergency. I don't like Donald Trump, and I would rather not see him as President, but nothing he has done convinces me that this is such a time. Vote for Hillary if you want but support Bernie. We need an ongoing democratic socialist presence, not a series of hiccups.