Be careful here. It would also be easy to say that Trump was soft on illegal immigration before he was against it (he thought Romney was too tough on the subject), and that he was for abortion on demand before he was against it. If you want others to accept that Trump could change his views on those subjects, you need to also accept that Carson can change his views on them.
CARSON has never explained why he changed his viewpoints. It appears his change of heart is poll driven.
TRUMP has sincerely explained his positions before he even ran for POTUS.
CRUZ has been on the right side every time. CRUZ 2016