In all this, Mr. Trump’s opponents treat norms as if they were laws. But Mr. Trump openly campaigned in 2016 as someone who would rescind the nonlegal norms of American politics. He said he would “drain the swamp.” Washington’s traditional way of doing business, the legal but corrupt trade in money and influence, was something he was elected to attack. He has only contributed to the problem in the eyes of his critics, but for supporters the goal remains the same.

Mr. Trump was also elected to transform America’s foreign relations. The nation’s leadership in both parties and the Civil Service had embroiled the country in endless wars and a string of humiliations. That Mr. Trump considers officials serving in places like Ukraine to be part of the problem he was elected to solve is no secret. The testimony such officials have so far offered during impeachment hearings bears him out: Their view of American objectives is different from his. Such differences are supposed to be decided publicly, through elections. Mr. Trump happened to win the last one.

President Trump was doing exactly what voters elected him to do when he asked President Zelensky to account for Ukraine’s dealings with the Bidens. It’s a question related to the overall system linking American politicians with Ukrainian interests. No doubt Mr. Trump sees that system as reflecting more poorly on Democrats than on his own party or himself. But exposing that system, whatever its partisan overtones, is both a legitimate interest of the United States and something that Mr. Trump’s voters expect of him in light of his 2016 campaign.