- May 2014
We are talking about the same period of time where Southerners were staging coups against Republican governments in the South and massacres and the government wasn't really intervening. They wouldn't have given up schools with any less of a fight.
As for the rest, my argument is not that Southerners would have been less "obstinate", it's that someone other than Andrew Johnson would likely not have encouraged violence by leniency and also would have responded more forcefully to violence that did occur, which can be a powerful deterrent. Compare Eisenhower throwing the military into desegregating Little Rock with the response to the Kennedys temporizing with the authorities during the Freedom Rides, the former went a lot more smoothly.