HOUSTON - What happened in the UK this summer caught the world by surprise: Brits voted to leave the European Union.

The final vote: 52% Leave. 48% Remain. Days before the Brexit vote, pollsters showed "Remain" with a lead. Betting markets and experts gave "Remain" an 88% chance to win. But they were all wrong.

Now across the pond, the U.S. is on the verge of its own election. Experts give Clinton an 84.7% chance to win. Trump disagrees.

"We have to get out and vote," said Trump. "This is going to be Brexit times five. Watch what's going to happen."

Nigel Farage, the architect of the Brexit victory, was able to rally voters in the UK right before the vote. But political analyst Bob Stein says the U.S. is not the UK. The anti-immigrant isolationist message that fueled Brexit is unlikely to lead Trump to victory due to changing demographics.

Also problematic for a Brexit-type surprise here is most states conduct massive early voting operations.

"If Donald Trump is telling you there's a last minute surge, the problem with that is that votes have already been cast and will be cast in the next few days," said Stein.

Finally, Stein says look at the data. Since the conventions, approximately 1,600 polls have been conducted. Almost all of them tell the same story - Clinton appears to be on the path to a huge electoral college win. So if she loses, Stein says, there may be some truth to Trump's claim the election is "rigged".

"If Donald Trump does win the election he might be right," said Stein. "It will be rigged. It would be remarkable if all the polls were wrong."

The election is now 12 days away.