In an unprecedented moment in presidential history, conservative radio host Rush Limbaugh was awarded the Presidential Medal of Freedom during President Donald Trump's State of the Union speech Tuesday night.

Limbaugh was visibly emotional as the president spoke about his longtime friend, who announced Monday that he's been diagnosed with Stage 4 lung cancer. He was one of the Trumps' special guests at the address, which touched on economic development, school choice, health care, immigration and the military.

Critics took to Twitter to condemn the president's decision not too long after Limbaugh was presented with the award. Many pointed to his comments on then-graduate student Sandra Fluke, who he called a "slut" and "prostitute" on his show for supporting President Barack Obama's health care law.

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However, Limbaugh supporters applauded the honor and argued that his many deeds warranted the award. So what is the Presidential Medal of Freedom and how is it supposed to be awarded?

Presidential Medal of Freedom criteria

According to the White House, the Presidential Medal of Freedom was established in 1963 by President John. F. Kennedy and is the nation’s highest civilian honor.

It’s awarded by the president to those “who have made exceptional contributions to the security of national interests of America, to world peace, or to cultural or other significant public or private endeavors."

Past recipients have come from a range of fields and specialties, including public service, medicine, journalism, entertainment and business.

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Why did Rush Limbaugh get the Medal of Freedom?

In his address, the president thanked Limbaugh for his "decades of tireless devotion to our country" as the conservative commentator broke into tears.

"In recognition of all that you have done for our nation, the millions of people a day that you speak to and that you inspire, and all of the incredible work that you have done for charity, I am proud to announce tonight that you will be receiving our country’s highest civilian honor, the Presidential Medal of Freedom," President Trump said before a chamber of thunderous applause.

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Trump told television anchors at a private lunch earlier Tuesday that he planned to award Limbaugh the civilian award as early as next week. The pair have occasionally golfed together and were seen eating lunch together at Trump’s West Palm Beach golf club just before Christmas.

“There is nobody like him,” the president tweeted after learning of Limbaugh’s cancer diagnosis. “Looking for a speedy recovery for our friend!”

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Has the medal ever been given out during the State of the Union?

The longtime conservative radio talk show host was presented the award by First Lady Melania Trump in the middle of the president's State of the Union speech.

This is the first time the prestigious medal has ever been awarded to an individual mid-speech during a State of the Union address. It's traditionally given out at the White House.

Presidents have bestowed the medal 14 times, including to athletes and celebrities like Tiger Woods, Babe Ruth and Elvis Presley.

Who has received the Medal of Freedom?

A number of well-known icons throughout history have been honored with the medal including Steven Spielberg, Muhammad Ali, Nancy Reagan, Mother Teresa, Rosa Parks and Martin Luther King, Jr., according to the White House.

Contributing:Courtney Subramanian, USA TODAY. Follow Adrianna Rodriguez on Twitter: @AdriannaUSAT.