AMES, Iowa - Real estate and reality television mogul Donald Trump descended on Iowa Saturday with a series of stern warnings for his party on immigration reform and the 2016 presidential election.

The immigration reform bill that passed the Senate and is now facing an uncertain fate in the House of Representatives "could be a death wish for the Republican Party," Trump said, alluding to the millions of undocumented immigrants who could eventually get the right to vote.

"Every one of those people - virtually - will be voting Democratic," he said. "They're not voting Republican."

Trump spoke at a forum organized by the Iowa-based conservative group, the Family Leader, on the campus of Iowa State University - the site of the quadrennial Ames Straw Poll, which was held two years ago this week.

Looking ahead to the 2016 presidential campaign, Trump predicted that "Hillary is going to be tougher to beat" than President Obama was last year. He urged Republicans to pick "the right person, the perfect person" to be the party's nominee.

If the party fails to do so, he said, "Republicans are going to get drubbed in the 2016 election - and that's not going to be a good thing."

Recalling the 2012 presidential campaign, Trump said he was fond of Mitt Romney "personally," but "I don't know what the hell happened with his campaign." He also complained that the Romney campaign didn't use him as a campaign surrogate enough during the general election: "I think they felt I was a little controversial."

He also found humor in his plans to build a brand-new hotel in the Old Post Office on Pennsylvania Avenue in Washington, D.C.

"Can you believe this?" Trump asked. "You have the White House, you have Congress and I'm building right in the middle!"