Democratic presidential candidate Sen. Bernie Sanders, D-Vt., speaks at a campaign event at Drake University on June 12 in Des Moines, Iowa. Getty Images

A writer for the National Review, a conservative news and commentary magazine, was lambasted online Monday night for penning an article in which, some argue, he called Vermont Sen. Bernie Sanders -- who is running for president in 2016 -- a Nazi. Kevin Williamson made the controversial comparison in a recent article titled "Bernie's Strange Brew of National and Socialism," which ran in the magazine's July 6 print issue but went online Monday.

Williamson wrote:

In the Bernieverse, there’s a whole lot of nationalism mixed up in the socialism. He is, in fact, leading a national-socialist movement, which is a queasy and uncomfortable thing to write about a man who is the son of Jewish immigrants from Poland and whose family was murdered in the Holocaust. But there is no other way to characterize his views and his politics.

He went on to criticize Sanders' stance on trade with China, then continued:

There are many kinds of Us-and-Them politics, and Bernie Sanders, to be sure, is not a national socialist in the mode of Alfred Rosenberg or Julius Streicher. . . He is a national socialist in the mode of Hugo Chavez. He isn't driven by racial hatred; he's driven by political hatred. And that's bad enough.

Outlets like Think Progress jumped on the phrase "national socialist" Monday night, linking it to National Socialist Party of Germany that dissolved in 1945. In other words, some argued, Williamson had labeled Sanders -- a self-described Democratic socialist -- a Nazi.

Among the people calling out Williamson for his terminology was Matthew Yglesias of Vox. Williamson took to Twitter Monday night to defend what he wrote, saying he never described Sanders as a Nazi.

Sanders grew up in Brooklyn "very conscious as a kid that my father’s whole family was killed by Hitler," Politico reported he once said, and at the annual convention for the National Council of La Raza earlier this month, he explained that the Holocaust taught him what politics was about. At the convention, Sanders said he was proud to be Jewish and hoped to fight racism, according to JP Updates.

"America becomes a greater nation, a stronger nation, when we stand together as one people and in a loud and clear voice we say no to racism and bigotry," he added.