Economic talks between the United States and Japan, tackling topics from persimmons and potatoes to energy and infrastructure, have helped keep Tokyo clear of protectionist moves such as those that recently hit Chinese solar panels and South Korean washers.

Japan hopes its "let's talk" approach — along with warm personal ties between Prime Minister Shinzo Abe and President Donald Trump — will keep friction in check. But officials and lawmakers say the outlook could change if the unpredictable U.S. leader turns his attention to Tokyo's ¥7 trillion ($63.62 billion) trade surplus before U.S. congressional elections in November.

"Naturally, America wants an early conclusion to what to do about its trade deficit (with Japan). Of course, they are concerned about the midterm elections and may say various things," said a ruling party lawmaker well-versed in U.S.-Japan economic ties — one of eight officials and lawmakers interviewed by Reuters who declined to be identified because of the sensitivity of the subject.