To say that this does not in itself rise to the level of “obstruction of justice” is to empty that concept of all meaning. Obstruction of justice was the first count in the articles of impeachment against Nixon and, years later, a count against Bill Clinton. In Clinton’s case, the ostensible obstruction consisted solely in lying under oath about a sordid sexual affair that may have sullied the Oval Office but involved no abuse of presidential power as such.

But in Nixon’s case, the list of actions that together were deemed to constitute impeachable obstruction reads like a forecast of what Trump would do decades later — making misleading statements to, or withholding material evidence from, federal investigators or other federal employees; trying to interfere with FBI or congressional investigations; trying to break through the FBI’s shield surrounding ongoing criminal investigations; dangling carrots in front of people who might otherwise pose trouble for one’s hold on power.

It will require serious commitment to constitutional principle, and courageous willingness to put devotion to the national interest above self-interest and party loyalty, for a Congress of the president’s own party to initiate an impeachment inquiry. It would be a terrible shame if only the mounting prospect of being voted out of office in November 2018 would sufficiently concentrate the minds of representatives and senators today.