Likeliest or best VP choice for Clinton?

[Lyin' Steve]

Tim Kaine is the likeliest pick, maybe the best.

Though I think there may be pressure on Clinton to pick Julian Castro, especially if Rubio is the GOP nominee.

Why are so many people confident that Clinton will select Kaine? Do they have some close history that I'm unaware of, or is it the fact that Kaine represents a swing state in the Senate? Kaine is a conservative Democrat. Joe Manchin would be a better selection for VP; for some reason, he has a record as a conservative Democrat, but he is less of a hawk on foreign policy than Hillary Clinton, opposed TPP and Fast Track (unlike Kaine), and has a record of bringing together Democrats and Republicans and breaking gridlock, especially with the Manchin-Toomey Amendment (universal firearms background check; unlike Kaine) in 2013. I think O'Malley or Manchin would both be good selections for VP, but not Tim Kaine. I can't understand where all this love for Tim Kaine is coming from.

Kaine has a solid history with mayor, governor, DNC chair, and now senator under his belt, with very strong approval ratings.  He was mentioned as VP in 2008 and was one of Obama's final three picks.
Kaine appeals to moderates, Catholics and working-class whites while not being revolting to liberals and minorities.  He also has considerable appeal to Hispanics having done lots of mission work in Central America.
Kaine has proven the ability to win tough races, beating strong opponents in Virginia by comfortable margins without selling his soul.
Kaine has no scandals or negative traits.
Kaine always seems like a charismatic guy who's easy to vote for.

This unlike Manchin, who will turn off liberals with his conservative votes and reputation, or O'Malley, whose negative traits are already very well-known (a very poor record as mayor, lousy political skills and a boring personality).  Kaine is a solid pick who balances the ticket while carrying Virginia, being relatively impervious to criticism, and adding net positives in a diverse array of fields.