By Bob Egelko

Ads attacking U.S. military aid to Israel were posted on Muni buses in San Francisco this year without incident. But Seattle's public transit line rejected the ads after threats of violence, and on Wednesday a divided federal appeals court upheld its decision.

The ads, sponsored by the Seattle Mideast Awareness Campaign, read, "Israeli War Crimes. Your Tax Dollars at Work." Municipal transit lines in several cities, including San Francisco, have carried them. In San Francisco, Muni has also accepted competing ads from anti-Islamic activist Pam Geller. One of those ads displayed a photo of Adolf Hitler and a Palestinian leader with the slogan "Islamic Jew-Hatred: It's in the Quran."

King County officials in Seattle initially agreed to accept the ad against Israeli aid in late 2010, but backed off after getting an avalanche of e-mails, some threatening disruptions or violence. The county's Metro transit system, which had previously carried ads critical of Israel and other political messages, changed its policy after the incident and barred all political and ideological advertising on buses.

A federal judge ruled in the county's favor, and on Wednesday, the Ninth U.S. Circuit Court of Appeals in San Francisco upheld that decision, saying that rejecting the ad did not violate freedom of speech.

The county had a reasonable policy of barring objectionable messages that were likely to disrupt the transit system, and in this case faced the real prospect of vandalism and other acts that could have endangered passengers and reduced ridership, Judge Paul Watford said in the 2-1 decision. He said the county's actions were "viewpoint-neutral" because they applied equally to anti-Muslim ads.

Dissenting Judge Morgan Christen said the county had abruptly changed its previous policy "in response to public uproar -- a particularly dangerous practice in light of modern technology" and instant communications.

(c)2015 the San Francisco Chronicle