Garcetti, Greuel and Perry are all essentially the same candidate. One of them will face Kevin James in the run-off, and it doesn't really matter which one because they're all exactly the same.
So if you're running a union, why bother spending your money on one of the three indistinguishable career politicians in the primary, when you've got only a one in three chance of guessing right? You thought Carmen Trutanich would be a shoe-in, remember? But the people of Los Angeles are actually paying attention now. The rules of the game have changed. Your old game theory doesn't work any more. You union leaders hold therefore let Garcetti, Greuel and Perry duke it out on their own in the primary.
Or you can ignore my sage advice, and instead pick one of the Philosopher Kings to support, fund his or her attacks on the others, and then, when your chosen one loses -- just as Trutanich lost -- you will have helped given Kevin James plenty of ammunition to attack either of the other two who survives the primary.
Game theory's a bitch when the voters refuse to fall for your phony ads, isn't it?
While you're at it, you should also seriously consider the fact that Kevin James is the only candidate who can turn this City around and make it thrive again. Your puppet candidates, if elected, will have to declare bankruptcy, and you can kiss your pensions and you contracts good-bye at that point. You want a really smart move? Back Kevin James in the primary and the run-off. Bankruptcy is not your friend.