President Donald Trump's campaign stop in San Antonio Wednesday evening drew enthusiastic supporters, vocal protesters and plenty of political fanfare, but a local political science professor says the visit is unlikely to make much of a difference at the polls.

With early voting less than two weeks away, Trump's decision to campaign in historically Republican Texas is also raising questions about how competitive the state's political landscape has become ahead of the Nov. 3 midterm election.

David Crockett, a political science professor at Trinity University, said Trump's appearance could energize his most loyal supporters but is unlikely to persuade voters outside his political base.