Attendees wait for Republican presidential candidate Donald Trump to speak at a campaign rally in Burlington, Iowa. (Scott Olson/Getty Images)

BURLINGTON, Iowa — Each time Donald Trump mentioned illegal immigration, the few thousand people who gathered at his Wednesday evening rally roared with applause and cheers accented with shouts of endorsement. This was his sort of crowd, and Trump seemed to feed off this encouragement, amplifying his usual comments.

As he does in nearly every speech, Trump criticized Ford Motor Company for its plan to spend $2.5 billion on a new plant in Mexico and detailed how he would bully Ford into building that plant in the United States instead. Trump said Hillary Rodham Clinton, the Democratic frontrunner, "is not going to have a clue" as to how to do this and would likely fold under pressure from Ford's lobbyists.

And then Trump kept going: "I mean, the way our country is run, if it doesn't happen to be me that wins, you know what's going to happen? They're going to build a plant and illegals are going drive those cars right over the border." As the crowd laughed and cheered, Trump one-upped himself yet again, taking one more jab at illegal immigrants: "And they'll probably end up stealing the cars."

[Sí or no? GOP divided over how tightly to embrace Latinos and Spanish]

In the more than four months that Trump has been running for president, a number of controversial issues have come and gone from his stump speech, keeping up with the subtly changing moods of his supporters. But illegal immigration has remained firmly in the line-up, guaranteed to excite conservative audiences across the country. And each time Trump makes a joke or harsh comment about immigrants, he yet again angers immigration activists and many Latinos, spurring protests and boycotts.

In announcing his candidacy in mid-June, Trump said the "U.S. has become a dumping ground for everybody else’s problems" and that Mexico is "sending people that have lots of problems." In setting the tone for his campaign, Trump said: "They’re bringing drugs. They’re bringing crime. They’re rapists. And some, I assume, are good people."

Those comments instantly sparked anger and a number of companies cut their ties with Trump, including Macy's department store, which once sold a line of ties carrying his name.

"When I started talking about illegal immigration, they thought it might not be politically correct — and now they don't sell my ties anymore," said Trump, who has surged in the polls since then and continues to dominate across the country. "Oh, and by the way, I know one thing: They wish they didn't do that because they would be selling more ties right now."

Trump said he doesn't understand this backlash or why he was "hit so hard by the media."

[Donald Trump says the media underestimates him]

"I love Mexico, and I love the Mexican people," Trump said. "I have thousands of Hispanics working for me, and they're great, and they do a great job."  

But that sort of wording is what rubs many Hispanics the wrong way, including celebrity chef José Andrés, a Spanish immigrant who backed out of plans to open a restaurant in the hotel Trump is building in D.C. The Trump Organization has sued Andrés for $10 million.

"They Don't work FOR You,"Andrés tweeted on Wednesday night, "They work 'With' You...."

But those sorts of sentiments were drown out Wednesday night by a crowd that laughed at Trump's jokes as if they had never heard them, cheered on his campaign promises and kept interrupting him with chants of: "Trump! Trump! Trump!" At times, it seemed like Trump was having a conversation with the audience rather than giving a speech.

Early in the night, Trump marveled that Army Sgt. Bowe Bergdahl is not expected to serve jail time for abandoning his post in Afghanistan, leading to his capture by enemy forces and the need for his rescue. A man near the stage mellowed: "Traaaaaaaitor!" Others in the crowd joined: "Traitor! Traitor!"

[Disillusioned and self-deluded, Bowe Bergdahl vanished into brutal captivity]

"That's right," Trump said. "What did we used to do to traitors?"

From the audience came suggestions like "Kill him!" and "Shoot him!"

"Six people died going after him and nothing's going to happen," Trump said. "Can you believe this? This is what has happened."

A few minutes later, as Trump started to bring up his distaste for political correctness, a man in the audience used an expletive to describe his own feelings on political correctness.

"It's true," Trump said, clearly delighted. "If I said that they would be writing horrible stories about me all the time. It's so good that he said that. I love that! Feel free to interject. I love that."

As Trump neared the end of his hour-long speech, he marveled at the crowd and its enthusiastic embrace of his sometimes politically incorrect stances.

"There's a movement going on," he said. "It's a strong movement. You know, they used to call it the silent majority? It's not silent. That term doesn't work."