Nancy Pelosi, speaker of the House of Representatives, decided this week to open a formal inquiry into the impeachment of U.S. President Donald Trump. The surprise move — Pelosi had long refused to take that step — followed revelations about a July phone call between Trump and Volodymyr Zelenskiy, president of Ukraine, that appeared to encourage foreign intervention in U.S. elections to benefit himself, and using the resources of the United States government to pressure Zelenskiy to do so. That, in conjunction with attempts to cover up that conversation, looks like grounds for impeachment.

At present, there is little reason to think that Trump will be removed from office even if the House votes to impeach. The Senate is controlled by Republicans and they remain steadfastly behind the president. Nevertheless, the process will have political and policy implications. Japan must be prepared for the impacts.

Progressives in the Democratic Party have been pushing Pelosi to open an impeachment inquiry since the 2018 midterm election that returned the House to their party's control. Pelosi resisted. Her top priority is ensuring an enduring Democratic majority in the House and that meant protecting the seats of moderates — the majority of which flipped to her party in that ballot.