My first presidential election was a disappointment. It was 2004, the year George W. Bush was reelected.
If Hillary Clinton wins the Democratic nomination--which I still think is the more likely option--there may be a lot of disappointed young voters. The danger is that, having seen their movement appear so powerful, Bernie Sanders' young supporters may become disillusioned with the voting process if that movement is not successful. What they need to realize is that their setback is a minor one compared to 2004's.
The same people who got excited for Bernie should be the same ones who fervently vote against Trump--if they are willing to stay in the game.
Then they'll just need to do a better job voting against than we did.