Is this statement racist? Sure. Is it an appeal or at the very best a smug wink at terrorism directed against a U.S. Senator and Democratic presidential nominee? Sure. If a private citizen made such a statment in a letter or before the Democratic convention would he or she not be arrested? Of course. If the commentator had said "Murdoch, McCain" instead of "Osama Obama" would she now be fired and also unemployable in the media that the rightwing calls "liberal?"
I doubt that the commentator will be arrested under the Patriot Act and put into preventive detention at Guantanamo (I would not support that although if the shoe were on the other foot I am sure Fox would). I doubt there will be an FCC investigation, given the composition of the FCC. I also doubt that the INS will launch a deportation case against Murdoch for using his media empire to foment terrorism (the present government in Australia anyway would not be to his liking). But what the Democatic Party and all progressive and anti-racist groups should do is call upon advertisers to end their advertising on Fox and call for a boycott of the products of those who don't. That Murdoch would understand.