Once Trump signs a loyalty pledge, he will be attacked ruthlessly and marginalized. When he refuses to do the same he makes all walk on eggs. The truth is that an agreement not to run would not be enforced by law.
He was very very clever in his comments about supporting conservative principles. All he has to do when Jeb wins is say Jeb does not represent the Republican Party, but is a RINO as our choir of forum crazies do here regularly, and then will simply name his independent movement, the REAL Republican party.......his words were carefully crafted.