Yes, We Kaine

So in a predictable, somewhat anticlimatic manner fitting the man himself, Tim Kaine has been tapped as Clinton's running mate.  This is, as Ezra Klein notes, a safe choice.  Kaine doesn't guarantee winning Virginia, but clearly and correctly, Clinton believes that winning Virginia is a big part of winning the election.  The "DC Establishment" extends into Northern Virginia, and many of them can't stomach Trump.  Kaine gives a few more of them license to vote for the relative safety of a Clinton-Kaine ticket.

So, why Virginia?  Let's give Clinton the states that 270 To Win gives her as safe: All the Northeast except PA and NH, the West Coast and Hawaii, NM, IL, MI and MN.  That's a reasonable floor.  You can argue that PA isn't really in play, but let's go with that.  If you add Virginia and Wisconin to the Democrats, Clinton now sits at 240.  Let's add Nevada and Colorado, with their large Hispanic populations.  Now we are 255.

That leaves Florida, Ohio, Pennsylvania and North Carolina out in the cold.  She wins either of those states, she wins.  Turning Pennsylvania has been a dream of the GOP for years and it's never happened.  The most recent poll in Florida has Clinton +7.

Winning Virginia really narrows Trump's ability to get to 270.  In fact, my conservative take right now has Clinton with 314 EV.  But I can realistically see a map with 384 EV.  That's a map where Trump continues to scare the shit out of people, making more and more unforced errors, and with Gary Johnson siphoning off just a few votes from Trump.

As for Kaine himself, aside from being safe and reassuring, he makes an interesting play for "Francis Catholics" and can do Hispanic outreach better than most white dudes.

Kaine has, however, predictably set off caterwauls from the Left.  He is not a pick used to mollify the  Sanders wing of the party.  As Martin Longman correctly notes: tough shit, he's a solid pick.

Kaine isn't a "Blue Dog" but he's as close as you could plausibly imagine being the VP pick.  Clinton believes that playing for the center could get her potentially more votes in the House.   She also knows and trusts him.  Tim Kaine - like Hillary Clinton - can make a reasonable claim to being well-prepared for the presidency.  Trump can't make that claim.  (I mean, he will, but...)

The Conventional Wisdom is that "2016 is a crazy year and anything can happen!"  I don't think that's necessarily true.

Brexit was crazy, but it was also crazy-close.  Austria almost elected a right wing nationalist.  But they didn't.  Trump won the nomination, but he isn't creating an electoral coalition that can win in November.

Trump hasn't rewritten the rules of politics.  He's served as an avatar for Angry Republicans.  That can only get him so far.