With all the insane stuff Donald Trump has been saying, this horrible statement fell through the cracks. But amidst all the other craziness from Trump today, he broadly hinted that if important US ally Japan were attacked, he’d walk away from the NATO treaty unless Japan coughed up enough money.

Donald Trump has attacked Japan, one of America’s closest allies, stating that if the US is attacked, all Japan would do is “sit home and watch Sony television”.

He expressed his frustration that the US is bound by treaty to defend the Asian nation but that if the United States is attacked, the Japanese cannot help because of Article 9, which constitutionally forbids it to send armed forces overseas.

He said that it “could be necessary” for the US to walk away from the treaty - or at least threaten to do so.

At a campaign event in Iowa, Mr Trump also repeated his criticism of countries that do not pull their weight in terms of financial contributions to Nato.

“You know we have a treaty with Japan, where if Japan is attacked, we have to use the full force and might of the United States,” he said.

“If we’re attacked, Japan doesn’t have to do anything. They can sit home and watch Sony television, OK?”

Mr Trump added that the United States protects Japan, South Korea, Germany, Saudi Arabia and other nations, and “they don’t pay anything near what it costs”.

“They have to pay. Because this isn’t 40 years ago,” he added.