In his new book, “Time to Get Tough,” Donald Trump lashes into President Barack Obama and threatens to run against him next year if the Republicans don’t nominate a strong candidate.

Beating the drum even louder, Mr. Trump details his net worth—which he puts at $7 billion—and says he’s prepared to pour a large chunk of his $270 million in liquid assets into a presidential bid. (Mr. Trump values the Trump brand alone at $3 billion.)

“He’s prepared to finance an independent run for president if he’s not satisfied with the Republican nominee,” says the real estate mogul’s right-hand man, Michael Cohen.