The presidency used to be a more unstable perch

Seeking to encourage Democrats to focus on the task ahead in 2020, pundits keep reminding their audiences (that's us) that "most presidents get re-elected."

Yet for a still significant slice of the electorate, a slice that largely can be counted on to vote, that's not the experience of our formative years.

Between 1960 and 1980, no president completed two consecutive terms.

• John F. Kennedy -- assassinated in 1963 in his third year in office

• Lyndon Baines Johnson -- a vice president who succeeded Kennedy, elected for one term in a landslide in his own right, then became so reviled because of the Vietnam War that he chose not to run for re-election

• Richard Nixon -- elected in 1968, re-elected in 1972, but resigned rather than be impeached in 1974

• Gerald Ford -- an appointed vice-present (the elected one was a crook who had quit) who served out the last two years of Nixon's term

• Jimmy Carter -- elected in 1976; lost to Ronald Reagan in 1980.

If John Hinckley Jr. been a more accurate shooter, might this pattern of incomplete presidencies have continued?

Since 1980, all sitting presidents have been re-elected except George H.W. Bush. But there is nothing fixed in that rather recent, orderly, pattern. It should not surprise if, in our current situation of contentious changes and incompatible demands, if we were to revert to a less stable condition. That feels promising at this moment -- also a little scary, but certainly possible.

Erudite Partner and I kicked this history around a bit; she helped settle my thinking.