TIM CAVANAUGH: Obama mum after May Day riot re-ruins Seattle.

The morning after hipster rioters turned a May Day demonstration into a replay of the 1999 Battle in Seattle, President Obama boarded Marine One and departed for an overnight retreat without commenting on unrest in U.S. cities that has spread to the Pacific coast.

The president stopped to fist bump with the child of an Associated Press staffer on a sunny Saturday before choppering out of the capital. But he made no comment on the Friday night rioting in Seattle, Wash.

Seattle rioters threw bottles and bricks at police; smashed and tagged property; and attacked reporters and other civilians in unrest that left three officers injured. Police Chief Chris Fowler declared Friday evening that the situation had “turned into a riot.”

Obama’s silence on the mayhem in one of North America’s most progressive cities contrasted with his loquacity earlier in the week, when the president as well as his staff spoke at length after Baltimore erupted in destructive but non-lethal rioting. . . .

The Seattle riot also participates in a long history. The city was attacked by vandals, thieves and looters in 1999, under the pretext of protest against the World Trade Organization. Friday’s violence erupted during a celebration of May Day, which honors traditions of revolutionary destruction designed to raise worker solidarity, expose the contradictions of late capitalism, and usher in a fundamental transformation of economic reality.

Obama beguiled readers of his exquisitely wrought memoir Dreams From My Father with tales of his youthful friendships among Marxist poets and punk rockers. The self-declared communist Van Jones briefly served as the Obama administration’s “green jobs czar.”

But the president has been less eager to attach himself publicly to historic economic-justice movements, or to their extensive legacies of violence. He is presently lobbying Congress for a bill that would give more power to the executive branch in order to conclude a Pacific Rim trade treaty — an agreement strongly opposed by his own party’s left wing.

Seattle police responded decisively to Friday’s criminal frenzy, and by Saturday civil order had been restored in the city. Unlike Baltimore, Seattle is not governed entirely by members of the president’s Democratic party. One Seattle city council member belongs to the Socialist Alternative party.

Well, okay then.