From Ken Levine's blog today [emphasis in the original]:
This is the man you want controlling nuclear weapons? His aides don't feel he's responsible enough to have his Twitter account. This is the man you want at the helm during major international crises? It’s just terrifying. Yes, I’m a Democrat, and I’ve had this blog for eleven years. You never saw me write a post like this about Mitt Romney, or John McCain, or even George Bush. But this is different. This is life-threatening.