William H. Macy is one of those actors who can appear in something mediocre or even downright stinky, but come out of it smelling like a rose. He can always be counted on to perform well, even when he’s surrounded by mediocrity.

“Focus” isn’t bad so much as it’s disappointing. Based on an Arthur Miller novel, it’s full of moralizing, some of which is heavy-handed. Movies can preach, but they need to do it with less condescension than we’re getting here.

The setting is Brooklyn near the end of World War II. Macy plays his regular role — a weary, bedraggled nebbish, this time named Lawrence Newman. Lawrence has never married, lives with his mother, and is in charge of personnel at a large, dull company. He and his neighbors have a quiet street where everyone knows everyone, and where attitudes toward the local Jew, Finkelstein (David Paymer), have become increasingly antagonistic.

One day Lawrence begins wearing new eyeglasses, and suddenly everyone thinks he looks Jewish. He is fired from his job because of this, and has trouble finding another one for the same reason. Even longtime associates like his blowhard neighbor Fred (Meat Loaf Aday), while realizing he’s not really Jewish, can’t shake the notion that something’s amiss.

Lawrence meets Gertrude Hart (Laura Dern), a fellow Christian with the same problem he has. Their public appearances as a couple don’t help matters for either of them, and the persecution that’s been heaped on Finkelstein soon is visited on them, too.

The anti-Semitism mostly takes the form of garbage being dumped on the lawn, though there is some mild violence. Director Neal Slavin’s intent apparently was not to turn this into a nightmarish “Twilight Zone” scenario, but merely a bad dream, and to provoke some thought: Before he became victim to it, Lawrence often turned a blind eye to prejudice. Are the Fates teaching him something?

Well, of course they are; the movie won’t ever let us forget that. The performances from the principles are all very good, but the film takes too long to get where it’s going. Furthermore, Slavin directs this Arthur Miller novel so that it looks like an Arthur Miller play, and plays aren’t much fun to look at when they’re on film coming from a projection booth. Put this one in the category of decent material, good cast, and misguided execution.

B- (; PG-13, some very mild profanity, racial.)