Korea expert Victor Cha was widely expected to be nominated as the next U.S. ambassador to Seoul. A few days after being told he was no longer in the running, the former George W. Bush advisor publicly criticized the White House's North Korea strategy.

In a Washington Post op-ed published Tuesday, Cha stressed the dangers of a preventive military strike on Pyongyang — an option believed to be favored by President Donald Trump's team.

Such a move "would not stem the threat of proliferation but rather exacerbate it, turning what might be a North Korean moneymaking endeavor into a vengeful effort intended to equip other bad actors against us," argued Cha.

Reports first emerged last June that Cha, currently a Georgetown University professor and senior advisor at the Center for Strategic and International Studies, was set to be the U.S. ambassador to South Korea — a post that's been vacant since Trump took office.

But over the weekend, the White House notified Cha that he was no longer being considered, the Financial Times reported this week. Trump's team stopped returning Cha's calls in December after the strategist made his concerns known about attacking the North, the FT continued, noting that Cha was reportedly asked whether he could help manage the evacuation of American citizens from South Korea.