President Barack Obama was criticized for telling voters they would be able to keep their insurance plans intact under his healthcare overhaul, Obamacare, when in fact they couldn’t. And Republicans in the House and Senate have yet to fulfill their promise to swiftly repeal the very same healthcare legislation once they took control of Congress, which they did in the 2014 midterm elections.

Anger over those failures is partly what’s driving Republican voters toward Trump: In surveys, many respondents say they no longer trust elected officials. But Trump’s sweeping pledges could also be setting him up for a fall.

Trump may be promising too much, said Michael Wissot, a Republican strategist and lecturer at the University of Southern California.

“Convincing Mexico to pay for a fence along our border is unrealistic,” he said. “Deporting 11 million undocumented immigrants is a logistical nightmare. These are examples of putting himself in a very precarious position even if he were successful,” he said.