If memory serves me correctly, there was a similar phenomenon back in 1984, all these Republicans "jumping ship" to Walter Mundane.
This happens a lot; who remembers that in 1980, former U.S. Senator Eugene McCarthy (D-Minnesota) and Rev. Ralph Abernathy (successor to Martin Luther King), jumped the other ship to endorse Reagan?
Or that in 2004, the aged son of Dwight Eisenhower endorsed the Bostonian Billionaire?
It signifies.....not a whole lot.