A spokesman for the San Francisco Federal Reserve has emailed me to explain the anti-Ted Cruz tweet (This is What the "Politically Neutral" Fed Tweeted Out Last Night After Ted Cruz Won in Iowa.) :
Hey Robert, here’s you go:
It was an accidental post on the part of Bank employee, not an official statement by the Bank. Once the employee realized the mistake they immediately deleted their post and reported it to the Bank. We have taken steps to ensure this won't happen again.