John McCain barely beats out Bush to win the 2000 Republican primary and wins the election and wins re-election. Romney runs against Obama in 2008 to lose and Santorum loses a close election against Obama in 2012.
Bush finally runs in 2016 and wins the nomination. What does the map look like?
I will guess this:
Bush while not being a great fit for the Rust Belt, still wins by doing better than Trump out west, in the south and in the northeast.
George W. Bush: 317 electoral votes
Hillary Clinton: 221 electoral votes
Give or take WI, PA, NH, NM and ME-02.