Here's Dubya in October of 2000 complaining about 'racial' profiling of Arabs in US airports:
Less than a year later, 19 Arabs hijacked four commercial airliners and killed 3,000 Americans. At least one of them (and probably more)--the 'mastermind'--seemed suspicious to a ticket checker who kept him off a connecting flight to his ultimate suicide destination, but who didn't notify authorities about Atta because, well, when the emperor is telling you not to notice things, it can be career-killing for a functionary to raise about all those things he's noticing.
Trump was right to assert that Dubya did not, in fact, keep the US safe vis-a-vis 9/11:
Trump's candidacy is a referendum on a wall along the US-Mexico border. During the South Carolina debate, the success of his candidacy also became a repudiation of the Dubya/McCain/Graham/neocon Republicanism of the last two decades.
Tangentially, I still see assertions that Trump is a Clinton plant. Taking that absurdity as fact for the sake of argument, he'd still be worth supporting. He's illustrating that America-first populism is a winning formula for aspiring Republican presidential candidates. Irrespective of the ultimate outcome of his campaign, he's blazing the trail. Those following behind him will face less resistance than he has as a consequence.