[Waukesha, Wisc...] Dr. Ben Carson spoke to an overflow crowd on Thursday night about the need to uphold constitutional values, put government on a diet, and simplify our tax code.

The event, put on by Americans for Prosperity Foundation-Wisconsin at the Waukesha County Fairgrounds Expo Center, was attended by more than 2,500 activists.

An overarching theme from Carson's speech was his call to uphold the Constitution. "Our founders would turn over in their grave if they could see what is going on today," he said referencing the First Amendment.

Carson said that the Constitution is being trampled and, "We have to stop it." He mentioned that it is not a Democrat thing or a Republican thing, but an American thing.

Carson drew a comparison between government and a morbidly obese individual that continues to take in way more calories than are necessary. He said if they would reduce their caloric intake, they could get fit and then "start to run."

"There is 10 percent of fat in everything." Carson said, "If we cut 10 percent of fat out of every governmental department, we would still survive."

He also referenced the fact that "America is the child of every other nation in the world" but cannot make the mistakes that other world-leaders have made in the past. Carson said countries like Greece gave into political corruption and in very little time started to fail.

To keep America as a leader in the world, the doctor not only called for smaller government, he also said the tax code needs to be fair and flat.

"You make $10 billion dollars, you pay $1 billion. You make $10 you pay $1. What could be more fair than that?" Carson said.

Right now, he said that the top one percent in earners pay one third of the taxes. Carson said, "I don't think they pay their fair share, I think they pay more than their fair share."

As a doctor, Carson is very passionate about healthcare policy. He called Obamacare "a total mess" and pushed for the use of health savings accounts. His main concern was that government was involved, and that they would use the Affordable Care Act to infiltrate each American's life.

"If they get control of your health, they get control of you."

Carson also spoke about his concern for the future of our nation and ended his speech by discussing the importance of fiscal conservatism. "Our young people...will have no chance if we continue to destroy the economic foundation of our nation."

Dr. Ben Carson gained national attention in February as a speaker at the national prayer breakfast in Washington, D.C. He is a neurosurgeon at Johns Hopkins Hospital and has authored many books.