'Lock Her Up!' Hillary Clinton and the Unofficial Slogan of the 2016 Republican National Convention

A delegate holds a "Lock her up!" sign, referring to Democratic presumptive nominee Hillary Clinton, during the third day of the Republican National Convention in Cleveland on July 20. Mike Segar/Reuters

In 1964, the GOP was divided along ideological lines when it gathered for its convention on the outskirts of San Francisco. The moderate wing supported then–New York Governor Nelson Rockefeller, while the hardcore conservatives favored Arizona Senator Barry Goldwater.

The crowd booed Rockefeller when he called on the party to disavow ideological extremists who "feed on fear, hate and terror." And they applauded Goldwater when he belted out his impassioned defense: "Extremism in the defense of liberty is no vice," he said in his now famous acceptance speech. "Moderation in the pursuit of justice is no virtue."

Some pundits have drawn parallels between that contest and the grueling one that's taken place this year. Indeed, going into the Republican National Convention in Cleveland, many have wondered whether this GOP gathering would be equally divided. On Wednesday, Texas Senator Ted Cruz's glaring lack of endorsement for the nominee, Donald Trump, raised further questions about where the party stands. (Like Rockefeller, Cruz was booed.) But one sign that something resembling unity has congealed is the crowd's zealous determination that Hillary Clinton, the presumptive Democratic nominee, belongs in a prison cell, not in the Oval Office.

That determination has existed throughout the campaign, during which Republican leaders expressed their anger at how Clinton responded to the 2012 attack on the U.S. Consulate in Benghazi, Libya, and their frustration with the FBI for not punishing her for using a personal email server during her time as secretary of state.

But the anti-Clinton rhetoric seemed to reach a crescendo on Tuesday during New Jersey Governor Chris Christie's mock-trial speech about the former first lady. "Lock her up! Lock her up!" the crowd chanted, referring to her alleged crimes.

The phrase has since become the unofficial slogan of the RNC. By Wednesday night's session, delegates held "Lock her up!" posters and chanted the phrase throughout the program. "Lock her up, I love that," Pam Bondi, Florida attorney general, said during her speech.

Wisconsin Governor Scott Walker went a step further. "The simple truth is liberal Washington insiders created our problems, and Hillary Clinton is the ultimate liberal Washington insider," he said Wednesday. "If she were any more on the inside, she'd be in prison."

The stridence of the anti-Clinton sentiment in Cleveland goes beyond the "Lock her up!" slogan. During the first day, some at the convention wore mock campaign shirts that read "Hillary for prison 2016." Aerial banner ads called for Clinton's imprisonment as well, and later that day, Patricia Smith, a mother of a victim of the Benghazi attack, blamed Clinton personally for the death of her son.

A supporter of Republican presidential candidate Donald Trump sells flags while wearing a "Hillary for prison 2016" shirt at a pro-Trump rally near the Republican National Convention in Cleveland on July 18. Lucas Jackson/Reuters

During his speech the same night, El Paso County Commissioner Darryl Glenn mocked Clinton's wardrobe. "We all know she loves her pantsuits," he said. "But we should send her an email and tell her that she deserves a bright orange jumpsuit."

But perhaps the most outlandish example of anti-Clinton rhetoric came from New Hampshire state Representative Al Baldasaro. Earlier on Wednesday, he said Clinton should be "put in the firing line and shot for treason" in connection with the Benghazi attack. The comments put the U.S. Secret Service on alert, according to WMUR. Later on Twitter, Baldasaro, a Trump delegate, wrote: "As an American, I believe in the Constitution, freedom of speech and the rule of law: no one is above the law, not even Clinton."

Boisterous chants against opposing candidates are nothing new. (Remember "Drill, baby, drill!" from 2008?) And Republicans are not alone in demonizing the opposition; at the height of the public's disillusionment with the Iraq War, caricatures of Presidents George W. Bush dressed as Adolf Hitler cropped up at protests. But a glance at recent history doesn't show a spontaneous demonstration for jailing the other party's candidate. In 1972, Watergate was in its infancy, and so there were no "Jail Nixon!" chants inside the hall in Miami Beach where George McGovern was nominated. Protesters called Hubert Humphrey a war criminal outside the Democratic Convention in Chicago in 1968, but inside the hall there was no viral chant similar to "Lock her up!"

In the post-Nixon era, however, the criminalization of politics has become the norm—from the Iran-Contra scandal of the 1980s to the impeachment of President Bill Clinton in the 1990s, and the now constant calls for the appointment of special counsels for everything from the "Fast and Furious" operation against arms traffickers in Mexico to the IRS auditing process.

In a way, the idea that Clinton is a criminal candidate—as opposed to one with whom Republicans simply disagree—seems to be the ideological successor of the "birther" myth perpetuated against Barack Obama, which involved widely debunked claims that the president was not born in the United States. Trump played a prominent role in that movement, spending months publicly questioning Obama's original birth certificate. A spontaneous chant like this, however, marks a new level of animus.

Some 40-plus years after Goldwater's rebuttal to Rockefeller, perhaps his message has sunk in.