Democrats, your leading candidate is too weak to count on as a firewall. She might be able to pull off a general election victory against Trump, but then again she might not. Too much is uncertain this year. You, too, need to help the Republicans beat Trump; this is no moment for standing by passively. If your deadline for changing your party affiliation has not yet come, re-register and vote for Rubio, even if, like me, you cannot stomach his opposition to marriage equality. I too would prefer Kasich as the Republican nominee, but pursuing that goal will only make it more likely that Trump takes the nomination. The republic cannot afford that.