Obama out-neoconned the neocons, turned Democrats into the war party, and liberated Republicans. Then entered Trump.
The best thing that Obama did for the Republicans was to pick up and own the “War on Terror” issue. That finally frees Republicans up to focus on free market and civil liberties issues.
https://www.methylated.net/2014/10/11/the-best-thing-that-obama-did-for-the-republicans/