President Donald Trump is considering using his emergency powers to bypass Congress to get his border wall built. At least one legal expert says he can’t do it.

Napolitano said the president does have certain emergency powers.

“But he can’t spend money and he can’t take property unless the Congress has authorized it,” he said. “That’s directly from the Constitution.”

Napolitano added:

“If that were not the case, then President Obama could have declared, ’It’s a national emergency, there isn’t enough health insurance around, we’re going to start paying for it.”

Trump also can’t take money from other programs and use it for a wall.

“Otherwise, he’s bypassing the Congress and he’s not a president. He’s a prince,” Napolitano said.

Napolitano made similar comments earlier in the day on Fox Business.

Truman attempted to seize steel mills amid a strike during the Korean War. The Supreme Court ruled that he needed Congress to pay for the steel mills and its workers.

“I think this is a bargaining technique,” Napolitano said. “Donald Trump is the master bargainer.”