It’s beginning to feel like a shoot-out at the O.K. Corral.

Yesterday’s indictment of Puerto Rico Gov. Anibal S. Acevedo Vila brings the tally of Democratic super delegates facing criminal indictments, or threat of indictments, to four. (Make that five, if you count former New York Gov. Eliot Spitzer, who was pledged to support Hillary Rodham Clinton, but resigned March 12 in a sex scandal and therefore lost his super delegate status.)