(MENAFN- The Conversation) In an unprecedented step, the Department of Defense announced online on Nov. 24, 2025, that it was reviewing statements by U.S. Sen. Mark Kelly, a Democrat, who is a retired Navy captain, decorated combat veteran and former NASA astronaut.

Kelly and five other members of Congress with military or intelligence backgrounds told members of the armed forces“You can refuse illegal orders” in a video released on Nov. 18, reiterating oaths that members of the military and the intelligence community swear to uphold and defend the Constitution. The legislators said they acted in response to concerns expressed by troops currently serving on active duty.

President Donald Trump called the video“seditious behavior, punishable by death.”

Retired senior officers like Kelly can be recalled to duty at any time, which would make it possible for the Pentagon to put Kelly on trial under the Uniform Code of Military Justice, although the Defense Department announcement did not specify possible charges. Defense Secretary Pete Hegseth wrote online that“Kelly's conduct brings discredit upon the armed forces and will be addressed appropriately.”

This threat to punish Kelly is just the latest move by the Trump administration against perceived enemies at home. By branding critics and opponents as disloyal, traitorous or worse, Trump and his supporters are resurrecting a playbook that hearkens back to Sen. Joseph McCarthy's crusade against people he portrayed as domestic threats to the U.S. in the 1950s.

As a historian who studies national security and the Cold War era, I know that McCarthyism wrought devastating social and cultural harm across our nation. In my view, repeating what I believe constitutes social and political fratricide could be just as harmful today, perhaps even more so.

Targeting homegrown enemies

In the late 1940s and early 1950s, many Americans believed the United States was a nation under siege. Despite their victory in World War II, Americans saw a dangerous world confronting them.

The communist-run Soviet Union held Eastern Europe in an iron grip. In 1949, Mao Zedong's communist troops triumphed in the bloody Chinese civil war. One year later, the Korean peninsula descended into full-scale conflict, raising the prospect of World War III – a frightening possibility in the atomic era.

Anti-communist zealots in the U.S., most notably Wisconsin Republican Sen. McCarthy, argued that treasonous Americans were weakening the nation at home. During a February 1950 speech in Wheeling, West Virginia, McCarthy asserted that“the traitorous actions of those who have been treated so well by this nation” were undermining the United States during its“final, all-out battle” against communism.

When communist forces toppled China's government, critics such as political activist Freda Utley lambasted President Harry Truman's administration for what they cast as its timidity, blundering and, worse,“treason in high places.” Conflating foreign and domestic threats, McCarthy claimed without evidence that homegrown enemies“within our borders have been more responsible for the success of communism abroad than Soviet Russia.”

From 1950 through 1954, Sen. Joseph McCarthy, a Wisconsin Republican, used his role as chair of two powerful Senate committees to identify and accuse people he thought were Communist sympathizers. Many of those accused lost their jobs even when there was little or no evidence to support the accusations.

As ostensible proof, the senator pointed to American lives being lost in Korea and argued that it was possible to“fully fight a war abroad and at the same time... dispose of the traitorous filth and the Red vermin which have accumulated at home.”

Political opponents might disparage McCarthy for his“dishonest and cowardly use of fractional fact and innuendo,” but the Wisconsinite knew how to play to the press. Time and again, McCarthy would bombastically lash out against his critics as he did with columnist Drew Pearson, calling him“an unprincipled liar,”“a fake” and the owner of a“twisted perverted mentality.”

While McCarthy focused on allegedly disloyal government officials and media journalists, other self-pronounced protectors of the nation sought to warn naive members of the public. Defense Department pamphlets like“Know Your Communist Enemy” alerted Americans against being duped by Communist Party members skilled in deception and manipulation.

Virulent anti-communists denounced what they viewed as inherent weaknesses of postwar American society, with a clearly political bent. Republicans asserted that cowardly, effeminate liberals were weakening the nation's defense by minimizing threats both home and abroad.

Censure and worse

In such an anxiety-ridden environment,“red-baiting” – discrediting political opponents by linking them to communism – spread across the country, leaving a trail of wrecked lives. From teachers to public officials, anyone deemed un-American by McCarthyites faced public censure, loss of employment or even imprisonment.

Under the 1940 Smith Act, which criminalized promoting the overthrow of the U.S. government, hundreds of Americans were prosecuted during the Cold War simply for having been members of the Communist Party of the United States. The act also authorized the“deportation of aliens,” reflecting fears that communist ideas had seeped into nearly all facets of American society.

The 1950 Internal Security Act, widely known as the McCarran Act, further emphasized existential threats from within.“Disloyal aliens,” a term the law left purposefully vague, could have their citizenship revoked. Communist Party members were required to register with the government, a step that made them susceptible to prosecution under the Smith Act.

Immigrants could be detained or deported if the president declared an“internal security emergency.” Advocates called this policy“preventive detention,” while critics derided the act as a“Concentration Camp Law,” in the words of historian Masumi Izumi.

Scapegoating outsiders

The scaremongering wasn't just about people's political views: Vulnerable groups, such as gay people, were also targeted. McCarthy warned of links between“communists and queers,” asserting that“sexual perverts” had infested the U.S. government, especially the State Department, and posed“dangerous security risks.” Closeted gay or lesbian employees, the argument went, were vulnerable to blackmail by foreign governments.

Fearmongering also took on a decidedly racist tone. South Carolina Governor George Bell Timmerman, Jr., for instance, argued in 1957 that enforcing“Negro voting rights” would promote the“cause of communism.”

Three years later, a comic book titled “The Red Iceberg” insinuated that communists were exploiting the“tragic plight” of Black families and that the NAACP, a leading U.S. civil rights advocacy group, had been infiltrated by the Kremlin. Conservatives like Arizona Sen. Barry Goldwater criticized the growing practice of using federal power to enforce civil rights, calling it communist-style social engineering.

In an interview on Oct. 13, 2024, then-candidate Donald Trump described Democratic Party rivals as 'the enemy from within' and suggested using the armed forces against 'radical left lunatics' on Election Day. A new McCarthyism

While it's never simple to draw neat historical parallels from past eras to the present, it appears McCarthy-like actions are recurring widely today. During the Red Scare, the focus was on alleged communists. Today, the focus is on straightforward dissent. Critics, both past and present, of President Donald Trump's actions and policies are being targeted.

At the national level, Trump has called for using military force against“the enemy from within.” On Sept. 30, 2025, Trump told hundreds of generals and admirals who had been called to Quantico, Virginia, from posts around the world that the National Guard should view America's“dangerous cities as training grounds.”

The Trump administration is making expansive use of the McCarran Act to crack down on immigrants in U.S. cities. White House adviser Stephen Miller has proposed suspending the constitutionally protected writ of habeas corpus, which entitles prisoners to challenge their detentions in court, in order to deport“illegal aliens,” alleging that the U.S. is“under invasion.”

In my home state of Texas, political fearmongering has taken on an equally McCarthyesque tone, with the Legislature directing the State Board of Education to adopt mandatory instruction on“atrocities attributable to communist regimes.”

Perhaps it is unsurprising, then, that right-wing activist Laura Loomer has unapologetically called for “making McCarthy great again.”

Disagreement is democratic

The history of McCarthyism shows where this kind of action can lead. Charging political opponents with treason and calling the media an“enemy of the people,” all without evidence, undercuts democratic principles.

These actions cast certain groups as different and dehumanize them. Portraying political rivals as existential threats, simply for disagreeing with their fellow citizens or political leaders, promotes forced consensus. This diminishes debate and can lead to bad policies.

Americans live in an insecure world today, but as I see it, demonizing enemies won't make the United States a safer place. Instead, it only will lead to the kind of harm that was brought to pass by the very worst tendencies of McCarthyism.

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