The United States can’t make deals with foreign countries unless it is prepared to walk away from negotiations, Donald Trump said Sunday as he dismissed complaints about his statements that Japan might need to build its own force of nuclear weapons.

“We’re going to Japan, and saying ‘You’ve got to pay more’ [for the cost of U.S. protective forces] … I want [the United States] to be reimbursed,” he told Greta Van Susteren at a Fox News town hall interview, Sunday evening.

“We [will] make a better deal, but you have to be prepared to walk,” he said, illustrating his style of high-pressure business negotiations.

“I don’t, I really don’t want Japan to go nuclear … I want them to pay — this is true for all countries,” he said.

“We’re not properly reimbursed … We’re like the policeman of the world,” he said.

Since Tuesday, March 29, when Trump threatened to pull military support from South Korea and Japan in the context of negotiations, Democrats have charged him with irresponsibility.

“What we do is really important to the rest of the world and even in those countries that are used to a carnival atmosphere in their own politics want sobriety and clarity when it comes to U.S. elections,” President Barack Obama said April 1.

“At some point we have to say, you know what, we’re better off if Japan protects itself against this maniac in North Korea,” Trump said March 29, adding, “I would rather see Japan having some form of defense, and maybe even offense against North Korea, because we’re not pulling the trigger.”

Also, South Korea should build up its own defense, he said, adding South Korea is likely to build a nuclear force regardless of U.S. actions. “It’s going to happen anyway,” he said March 29.

Since Trump spoke, Korean commentators have stepped up their long-standing calls for development of their own nuclear force to protect the nation from the nuclear-armed dictatorship in North Korea.