Transition From Barack Obama to Donald Trump Turns Tense

President Barack Obama and his successor Donald Trump are making moves that tread on each other’s turf and complicate the other’s agenda, creating one of the messiest White House transitions in recent years.

Since Election Day, Mr. Obama has taken some of the most far-reaching actions of his eight-year presidency, leaving Mr. Trump to manage the fallout and narrowing his options once he takes office. He also plans a final major address the week before the inauguration that will reflect on his policy agenda, according to...