"Donald Trump is a con man," Marco Rubio says. Rubio is right. Throughout his business career, Trump convinces the vulnerable that they can be his partners — when really they're his marks.

This campaign is Trump's latest con.

"Trump's voters are just the latest set of marks," conservative writer Michael Brendan Dougherty aptly put it, back before Iowa. "Like the graduates of Trump University, or those who dined on Trump's steaks."

The businesses that thought they were partners in Trump's casinos, the aspiring entrepreneurs who thought they were partners in Trump's real estate empire, the borrowers and salesmen who thought they were partners in Trump mortgage businesses — they were all the victims of his con.

Trump mortgage provides the perfect analogy.

Trump says that back before the financial crisis, he knew that housing "was a bubble that was waiting to explode." But at the time, Trump said on cable TV, "I think the market is very good," and he directed viewers to Trump Mortgage.

The Washington Post interviewed Jan Scheck, the sales director for Trump Mortgage: "I told myself, 'This is an awesome opportunity with somebody who is a god in the real estate industry,' " Scheck said. "People were buying Trump ties. . . . Everybody wanted to be Donald Trump. Donald was putting his name on buildings all over the country. I thought this was going to be an awesome opportunity."

It wasn't. The company folded. A subsequent failed Trump venture, Trump Financial, never paid saleswoman Jennifer McGovern hundreds of thousands of dollars it owed, a court ruled. But Trump had structured the company so that he was personally protected. McGovern never got the $298,000 the court said she was owed.

Dozens of former Trump "partners" suffered the same fate, including the jilted students of Trump University, and the many creditors whom Trump stiffed through bankruptcy. One South Carolina vending machine maker went in with Trump on his Taj Mahal casino, but later found Trump telling other creditors that he didn't plan on paying them for the money-changing machines they had sold him.

Trump will do the same if he wins the White House. A President Trump would not deliver the things that candidate Trump promises. He wouldn't deliver them, because in many cases he couldn't. In other cases, he would simply get a better offer from the special interests. And take it.

Trump is a dealmaker. That's half of his pitch and half of his appeal. Another popular Trump trait: "He's not in bed with the lobbyists," as voter Mike Benson told me after a Trump rally in Southwest Virginia. The second half of that notion is that Trump instead stands with the American people — specifically for his voters.

It's the type of populist message only a self-funding millionaire (riding on tens of millions worth of free coverage from cable news) can deliver. "They're controlled by the lobbyists," Trump said of his opponents "and they're controlled by the special interests. ... Nobody owns me."

But Trump's voters don't own him either. A good dealmaker only gives anything to someone who can give in return. Right now, he needs white working class votes to win GOP primaries with 30-45 percent of the vote. And so he gives the white working class some populist rhetoric, anti-trade tirades and a dash of white identity politics.

Once he's the nominee, if he's the nominee, Trump's needs will change. He'll need more liberal voters, he'll need the Republican establishment. He may need donors and super PACs. When the situation changes, a good dealmaker adapts.

Then, if Trump wins the presidency, Trump's incentives will change entirely. No special interest may own him, but he will nonetheless need them. Trump already admits his trade policy will involve convincing companies not to ship jobs overseas. Some of his persuasion will be gangster-like threats. But what sort of dealmaker only offers a stick? Trump will offer carrots.

You can bet he will cut a deal with the U.S. Chamber of Commerce on immigration. Maybe, I'll give you more low-skilled guest workers if you lobby the Senate to support my border wall. Trump won't give favors to the special interests out of indebtedness, but as a transaction — because everything for Trump is a transaction.

And when Trump is in the White House, the special interests will all have plenty to offer him. What will he need from voters at that point? While other candidates like Bernie Sanders, Ted Cruz and Marco Rubio have principles they subscribe to, Trump has none. It's all what can you give me?

If this year you give Trump your vote, thinking you're going into business with him, you should realize that you're not his partner — this is just his biggest con yet, and you're his latest mark.

Timothy P. Carney, The Washington Examiner's senior political columnist, can be contacted at tcarney@washingtonexaminer.com. His column appears Tuesday and Thursday nights on washingtonexaminer.com.