Supporters of President Donald Trump claim that the president did nothing wrong by delaying congressionally authorized military support to Ukraine—used in its defense against Russian encroachment—until its new president announced he was opening an investigation into Joe Biden and his son. What the president’s supporters have failed to articulate is what actions Mr. Trump could engage in that would be wrong and impeachable.

For, if conditioning military aid on a nation starting an investigation of a president’s political opponent is acceptable, would doing so to coerce a nation to investigate current political leaders causing problems for that president, such as the speaker of the House or chairs of congressional committees, be acceptable?

What about making U.S. aid conditional on that nation investigating or otherwise penalizing a nonpolitical opponent—say, Jeff Bezos, owner of The Washington Post, a frequent critic of the president?

If Mr. Trump’s actions have not passed his supporters’ threshold for impeachable conduct, what would he have to do to reach that threshold? Where is the line drawn?

Many of Mr. Trump’s older supporters favored impeaching President Bill Clinton for lying about a consensual sexual affair 20 years ago. But how was Mr. Clinton’s offense a greater threat to the Constitution than the conduct enumerated above?

I’d like to hear from Mr. Trump’s supporters what line the president would have to cross for impeachment to be warranted.

KENNETH A. PERKINS

Squirrel Hill

Note from KBJ: You first, Kenneth. What line would Barack Obama had to have crossed for impeachment to be warranted? Here's the line I draw: "The President, Vice President and all civil officers of the United States, shall be removed from office on impeachment for, and conviction of, treason, bribery, or other high crimes and misdemeanors." When you get one of those, we'll talk.