When past presidents were threatened with removal from office, their real troubles stemmed from transgressions committed while in the White House — not controversies that dogged them before taking the biggest oath of all.
Generally, presidents tend to be judged, as you'd expect, by what they do as incumbents rather than during the campaigns that got them there.
It would be a first for President Donald Trump to be accused of campaign-time collusion with Russia or Russians. Judging by past scandals, it would seem the claim that as president he tried to snuff an FBI probe would carry the greater danger for him.
The before-office or after question surfaces this week with special counsel Robert Mueller reportedly close to deciding if the Trump 2016 campaign illegally cooperated with a somewhat hostile foreign power — and whether the president obstructed justice after taking the oath.
According to Bloomberg News, no public accounting of the Mueller probe is expected before the Nov. 6 congressional midterm elections.
When Bill Clinton was impeached, the substance of the charges involved lying under oath about an affair that occurred in the White House with a young intern. The allegations, however, grew out of a lawsuit filed by former state employee Paula Jones, who had accused Clinton of sexual harassment during his time back in Arkansas.
Long before his election, rumors of Clinton sleaze were rife, involving personal finances and a knot of circumstances that his foes and critics called Whitewater, for the development corporation in which he invested. But the Whitewater controversy itself never jammed him up.
President Richard Nixon quit in the face of evidence that he used the tools of government to cover up criminal acts. But the mere fact that critics called him "Tricky Dick" for many years before he was president, and the stories that gave rise to the nickname, didn't seem to count against him once he was in power.
For Trump, recent reports about how he and members of his real estate family avoided taxes in unseemly ways in the 1990s don't seem to have tripped him up politically or legally, even as state and city officials in New York say they will have a new look back at the situation.
Maybe tradition will hold and the president will face no problems from whatever happened in the days before Jan. 20, 2017. Nobody can be sure yet.