I also agree Presidents probably get a briefing after elected and they find out many things that change how they previously thought.
No clearer example then how Obama went from this:
The fact that we are here today to debate raising America’s debt limit is a sign of leadership failure. It is a sign that the U.S. government can’t pay its own bills. ... I therefore intend to oppose the effort to increase America’s debt limit.”
“I think if you look at the history, getting votes for the debt ceiling is always difficult, and budgets in this town are always difficult.”
— President Obama, news conference, Jan. 14, 2013