Japan is worried about another 'transactional' Trump presidency, Tokyo-based expert says

There is a lot of uncertainty in Japan about the next few years as a "transactional" Donald Trump's possible return to the Oval Office has raised business and regional security-related concerns, author William Pesek said.

U.S. president Joe Biden's performance during the first presidential debate has "caused a bit of a shockwave across Tokyo," Pesek, author of "Japanization: What the World Can Learn from Japan's Lost Decades," told CNBC's "Squawk Box Asia" on Monday.

Biden performance has raised alarm bells in his own party with several colleagues urging him to drop out of the race.

Former House of Representatives Speaker Nancy Pelosi has refused to say she supports Biden as the Democratic nominee and major donors are refusing to finance the party until he steps down.

Pesek said that the Japanese government had been "pretty certain that Biden had this well in hand." However, following the recent turmoil in Biden's party, Japan's ruling Liberal Democratic Party is now reappraising the odds of a "Trump 2.0 presidency."

"I think the issue with Trump, he's very transactional, he's not very predictable. He's not very loyal in terms of relationships anywhere. Never mind Asia. If you're Japan, they're looking at the future and wondering, 'this could be a fascinating few years for for us.'" Pesek said.

A Trump presidency is concerning to Tokyo because Japan suffered from "collateral damage" during his first term, Pesek said.

"In many ways, a lot of his trade war policies were aimed at China, but Japan's economy suffered greatly during that period.

Trump has vowed a 10% across the board tariff on worldwide imports and 60% tariffs on China if he becomes president.

A paper by UK-headquartered Centre for Economic Policy Research in 2019