As a gentle reminder of the pervasively interconnected nature of Washington politics, a member of the Kennedy family posted a private photo on Facebook of herself with former president George H. W. Bush.

“The President told me he’s voting for Hillary!!” the accompanying note read, indicating that Bush — ousted from office by Bill Clinton — might now be planning to vote for the former first lady. Kathleen Kennedy Townsend confirmed the conversation by phone to Politico.

A spokesman for the former president said that Bush wasn’t going to publicly endorse anyone. As The Atlantic’s David Graham noted, this is the son of a Republican senator, is a Republican president, the father of another Republican president and the father of a former Republican governor. That he might be thinking about backing a Democrat, publicly or not, is remarkable.

After the party conventions, we noted that Clinton had lined up the support of all of the living former Democratic nominees for the presidency as well as the living presidents. Trump had the support of two of the five living Republican nominees and none of the past presidents. Trump insulted both of the aforementioned Bush sons during the campaign, so it’s probably not much of a surprise that George H.W. Bush wouldn’t rush to embrace him. But a public endorsement of the candidate from the opposing party would be pretty unique.

We tend to forget how few moments we’re talking about when we consider the endorsements of past presidents. Since the death of Franklin Roosevelt, there have been 50 elections in which a former president has been alive to endorse a possible successor. In 10 of those, no endorsement was offered (per our review of contemporaneous news reports), including George W. Bush this year. (Often, the lack of endorsement stemmed from illness or age, but Richard Nixon doesn’t seem to have been a sought-after endorser, for some reason.) In 39, the former president backed the candidate from his own party.

George H. W. Bush is the question mark.

These have not always been rousing endorsements, mind you. In 1972, Lyndon Johnson barely offered George McGovern his support.

Jimmy Carter feuded with Bill Clinton in 1992 but endorsed. In 1996, he skipped the Democratic convention. In 1956, Harry Truman backed someone besides the previous nominee, Adlai Stevenson, in the primary, but eventually came around.

The year 2016 will see the most former (or incumbent) living presidents since 2000, and, unlike that year, all of the public endorsements favor the candidate of one party. Granted, the living Republican presidents are all members of the Bush family, but it’s still a remarkable development.

Whether George H.W. Bush casts his ballot for Clinton, it’s the first time since 1976 that a living Republican president hasn’t endorsed the Republican candidate for chief executive. That, by itself, is significant.

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