I refer you to this piece on the 1960 election aftermath in Slate magazine.
A quick summary: Nixon may have done nothing himself, but his aides, and the Republican party, vigorously pursued all possible legal avenues. They sought recounts and demanded investigations in 11 states, grand juries were empanelled, court cases decided, appeals heard. The FBI even got in on the action. In Illinois, they demanded and got a recount, and when that proved insufficient, they went to Federal court. Rebuffed there, they took it to the State Board of Elections (4 GOP, 1 Dem at the time). They were rejected there too.
The national party finally threw in the towel on December 19, 1960, when the Electoral College voted. But one court case continued until December 28 of that year.
Given that some of Nixon’s closest aides - Bob Finch, Len Hall, Peter Flanigan - were involved in the effort, and that he could have easily come out publicly in opposition to the GOP’s efforts to undo the election, but didn’t - the idea that Nixon wasn’t involved is as ludicrous at the idea that Nixon had no idea what the Watergate conspirators were discussing in the office below his when they gathered together for Watergate damage control on June 20, 1972.
So let’s bury the ‘Nixon precedent’ for conceding gracefully for the good of the country. It didn’t happen.
Maybe one or the other of these two - we’re obviously divided as to which, but let’s save that for the other threads - should indeed concede gracefully for the good of us all, but citing Nixon as a reason just won’t fly.