so I guess Jeb! would be less of an immediate danger to civilization. But that's a pretty low bar.

Unless the Republicans end up doing a brokered convention, he simply will not have the delegates to play much of a role. He had his opportunity early on, and failed to gather enough support. He's going to finish far out of the running, grouped with the pack of other losers in this round.

Cruz, in my opinion, is not threat, except to the viability of the Republican Party. His teabagger ethic is not OK with a large mass of more or less moderate Republicans. They will not vote for him, and will either not vote or will vote for Clinton. Women, especially, are more likely to switch parties and vote for her if Cruz is the nominee.

Trump has the same problem. He's a non-starter in the general election.

Rubio? He's the unknown quantity, I think, for the General election. If he can pull things together, he could be a real challenger to a Democratic victory.

Those are more likely to be options.

Bush is a republican.

Both bad choices, but I would have to pick Bush.