Donald Trump said that one of his immigration policies if he gets elected as the next president of the United States would be fashioned after a 1950s initiative called Operation Wetback.

The repatriation project, which was created by the Director of the U.S. Immigration and Naturalization Service Joseph Swing together with the Mexican government, was enacted during former U.S. President Dwight D. Eisenhower's term, Fox News Latino reported.

In CBS' 60 Minutes Overtime, Trump said that his plan will deport all illegal immigrants in the country, only allowing them to return on a per-case basis work.

"We are rounding them up in a very humane way, in a very nice way, and they're going to be happy because they want to be legalized," the GOP frontrunner told CBS' Scott Pelley, as quoted by Fox News Latino. Trump added that plenty of people didn't know that Eisenhower's immigration plan worked.

Eisenhower's 1954 policy deported roughly 1 million undocumented immigrants to Mexico. Washington Post wrote that Operation Wetback was named after "the disparaging term for Mexicans who arrived in America through the Rio Grande, and considered by many immigration scholars as a painful part of national history because of the documented abuse that Mexican migrants suffered during and after their deportations." Then Attorney General Herbert Brownell, Jr. ordered officers to shoot point-blank wetbacks attempting to enter the U.S.

According to The Washington Post, hundreds of thousands of expelled Mexican nationals and U.S. citizens back then were transported into the deep Mexicali streets with no possessions and unable to go home.

"This was strategic: the more obscure the destination within the Mexican interior, the less opportunities they would have to return to America. But the tactic also proved to be dangerous, as the migrants were left without resources to survive," Washington Post wrote.

Back then, many of those expelled died from heat stroke. Other deportees shared poor quarters in vessels resembling slave ships, which headed to another drop-off point, the Mexican Gulf Coast. Historian Mae M. Ngai said that these were not anomalies, but were part of the Operation Wetback's vital framework, the news outlet added.

Rodolfo Acuña, professor emeritus of Chicano Studies at California State University, Northridge, told The Huffington Post that Trump "doesn't know what he's talking about" and Operation Wetback is the opposite of humane.

The Republican candidate also recently addressed the Syrian refugee crisis, saying that if he becomes president, he would immediately send them back, BBC reported. This went against his statement earlier in September when he told Fox News that the U.S. should take in more refugees fleeing from their civil war-torn country.