Iowa knows the presidential candidates better than anyone at this point. What I’m waiting to see tonight is who gets the Mad-As-Hell vote.

Bernie Sanders and Donald Trump are both pushing hard.

Trump went for the Christians, giving Jerry Falwell Jr. a lift on his private 757 with the gold-plated seat belts.

“I rode with him on the plane and I expected … champagne and caviar. He broke out Wendy’s cheeseburgers and fries,” he said.

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Bernie Sanders, who still flies coach, was scolding Hillary for her SuperPAC donations and he also had a message for billionaires like Trump.

“Enough is enough, you’ve had your day and now it is our turn,” he exclaimed.

Be prepared, because anything can happen. In Iowa, anybody can show up and anybody can register for either party on caucus night. And that’s where the Republicans might have an advantage, because they have a secret ballot.

The Democratic caucuses require you to physically move to your candidate’s table. Campaign volunteers can lobby you; they can tempt you with homemade coconut macaroons. And all your neighbors are watching you. You can’t hide who you’re for.

Whereas on the Republican side, as Donald Trump’s daughter Ivanka explains in a campaign ad: “It’s a secret ballot, you just write down the name ‘Trump’ and you’re done. That’s it,” she said.

For people who are shy, don’t want the neighbors to know their politics, or who just want to be home in time for “Jeopardy,” that could be very tempting.