Bernie supporters make the case to support Hillary
Every few days, there's a thread about Hillary stealing the elections, about Republicans using disenfranchisement to steal elections, about corporations flipping electronic voting machines to steal elections. If this is what you believe, then obviously Bernie is not up to the task. If he can't stop Hillary from stealing elections, just imagine what the Republicans and Wall Street will do to him.
As Sanders supporters have readily acknowledged, Hillary is in the pockets of Wall Street, so Wall Street won't mind her victory. They are far less likely to steal the election from her than from Bernie. So, with Hillary at least we'll get more gun regulation and better immigration reform than Bernie offers, and more than likely she'll be as responsive to her base (such as African Americans) as Bernie is to his (millennials). On other issues, she's not as good as Bernie, but we'll still get good progress on college costs, minimum wage, climate change, higher taxes on the wealthy, and increased regulation of Wall Street. Her foreign policy will be more liberal and less libertarian, so she will get the US more engaged in fighting ISIS, though I don't think she has other war plans. She also won't fight for single payer health care and will leave fracking up to the states.
But, given that our system is corrupt, it's hard to see how Bernie will win. If the Republicans and Wall Street can't defeat him with draconian election laws, then they'll flip the election electronically. It seems far less likely that Wall Street would support that type of action against Hillary.
The other choice, of course, is to believe that our system is fundamentally honest and, even with the occasional abuses, the winner is democratically chosen, and so Bernie can win.