The president used his clemency power to further undermine environmental laws and to help a political supporter who pleaded guilty in a fraud involving Jack Abramoff.
Florida officials had asked the justices to hear a lawsuit accusing California and Washington of improperly granting licenses to an immigrant accused in a fatal crash.
At an event in Washington, partisanship took a back seat as elected officials, religious leaders, parents and artists called for reining in artificial intelligence.