David Frum, writing for The Atlantic:

This November, however, I am voting not to advance my wish-list on taxes, entitlements, regulation, and judicial appointments. I am voting to defend Americans’ profoundest shared commitment: a commitment to norms and rules that today protect my rights under a president I don’t favor, and that will tomorrow do the same service for you.

Vote the wrong way in November, and those norms and rules will shudder and shake in a way unequaled since the Union won the Civil War.

Tuesday’s vote is not one between Hillary Clinton and Donald Trump. It’s between an America where The Great Experiment has a chance to continue, and one where our basest instincts threaten to overwhelm and doom the republic.