Is Russia's Paul McCartney a traitor? The Kremlin would like you to think so.

Last Sunday, about 25,000 people gathered in downtown Moscow for an anti-war rally to protest Russia's involvement in Ukraine's civil strife, billed as the "March for Peace."

In the central Pushkin Square, they were greeted by an enormous banner that read in giant letters, "MARCH OF TRAITORS." Beneath the words were the faces of some of Russia's leading artists, academics, and writers – including one of Russia's most venerable rock legends,  Andrei Makarevich – all of whom have been targeted by a mud-slinging Russian TV series over their anti-war stance and criticism of Kremlin policies in Ukraine.

The banner, which could only have been placed there with official permission, was a none-too-subtle warning amid a "whole new low" in the Kremlin's crackdown on dissent: using Joseph McCarthy-like tactics to smear critics as outright traitors to the nation.

A general crackdown on dissent has been underway in Russia since Vladimir Putin returned to the Kremlin for an unprecedented third term about two years ago. A wide variety of new laws have narrowed the space for public protest, forced politically active civil society groups who receive any non-Russian funding to self-identify as "foreign agents," and criminalized any public expression of gay identity. 

But the pro-Kremlin NTV network, owned by the state gas monopoly Gazprom, has stood apart in its willingness to use raw disinformation to defame and discredit Kremlin opponents.

Two years ago it produced a "documentary," using what were apparently leaked secret police video tapes and other doubtful sources, to claim that left-wing protest leader Sergei Udaltsov was part of a foreign conspiracy to overthrow the Russian government. Materials from the NTV film were later used in Mr. Udaltsov's trial, which saw him imprisoned this summer for a term of six years.

NTV's latest offering, entitled "Friends of the Junta" in reference to the post-Maidan revolutionary government in Ukraine, follows a similar arc. The series, which aired over the past month, targets about two dozen leading Russian figures using innuendo, suggestive imagery, guilt-by-association, and hearsay to make their varying degrees of criticism toward Kremlin policy sound like outright betrayal of Russia.

'Absolutely a traitor'

Mr. Makarevich, who is often likened to the Beatles' Paul McCartney for his multi-generational impact on Russian rock music, is the most prominent Russian celebrity to suddenly find himself under the gun. The first installment, "13 Friends of the Junta," focuses on a Makarevich concert in August, held in a town not far from the war zone in eastern Ukraine.

Never mentioning that Makarevich was holding a charity event to aid children displaced by the fighting, the show intersperses images of the iconic rocker singing with scenes of Ukrainian artillery firing on nearby rebel-held Luhansk – at that same time, it claims. An ominous voice-over describes the carnage that Makarevich was supposedly endorsing by performing "on behalf of the fascist junta" in Kiev.

Then it cuts to an interview with music producer Vadim Tsiganov, sitting with his famous wife, singer Vika Tsiganova. "Coincidences like that don't just happen," an angry-looking Mr. Tsiganov insists. "He will never cleanse himself of this [stain of performing as Russians died in Luhansk]. In the eyes of the average Russian, he is absolutely a traitor," he adds.

A stock image of sheets of dollar bills running off a printing press is the only evidence offered for an allegation that Makarevich might be betraying his country for foreign cash. A claim that the singer owns vineyards in Russian-annexed Crimea, on which he will now have to pay taxes to the Russian government, is supported only by unidentified footage of a vineyard.

'My Country Has Gone Mad'

Makarevich has always cultivated an image of liberal non-conformity, but even in Soviet times managed to avoid serious trouble with the authorities. In the past few years, however, as Russia has taken a sharp authoritarian turn, he's become more outspokenly anti-Putin. His public criticism of the annexation of Crimea in March led some parliamentarians to demand the Kremlin strip him of his state honors.

Following the airing of "13 Friends," Makarevich tried to appeal to Mr. Putin, with whom he once enjoyed close relations, in an open letter asking him to do something about the "dirt and libel that is being poured on me from the pages of newspapers and from television screens."

"The only 'crime' that I have committed is having given a charity performance in Svyatohirsk [Ukraine], in a camp for refugees from Donetsk and Luhansk, by singing three songs for the children of those refugees," Makarevich wrote. "For that, I feel no guilt."

The only response from the Kremlin was a statement by press secretary Dmitry Peskov that Putin had not been informed of Makarevich's complaint, but that he would be unlikely to interfere with "public discussion" of Makarevich's political preferences.

All of Makarevich's upcoming concerts have been mysteriously canceled, his website has been shut down, and his press spokesman says there will definitely be no comment. A new Makaravich song that's made its way onto YouTube, entitled "My Country Has Gone Mad," may speak volumes about his current state-of-mind, however.

Fear of a 'fifth column'

The Ukraine crisis, and Putin's handling of it, has brought a surge of patriotic spirit and notched up suspicion of the West and Russians who seem to reflect its values. Despite Putin's popularity spiking at over 80 percent, paranoia about internal enemies seems stronger than ever.

"Putin needs this fear of a 'fifth column,' an active enemy image, to distract people from everyday problems, economic slump, the growing isolation of our country," says Viktor Shenderovich, a famous Russian satirist who is featured in the NTV series for his persistent criticisms of the Kremlin.

"Using Kremlin-controlled TV to slander opponents is not new, but this is a whole new low," says Masha Lipman, an independent political expert. "Many of the people being targeted have made only mild remarks, and never said anything to deserve being tarred with the brush of treason."

"But people who have the status of celebrities, an independent base of popularity, and a vehicle to express themselves, have always been a particular concern to the Kremlin," she adds. "Anyone like that, with a dissenting opinion, is going to be regarded as potentially dangerous."

Many worry that the ongoing series foreshadows grimmer events ahead, just as it did for Udaltsov. "We know from experience," says Oleg Kashin, an investigative journalist who fled abroad after multiple threats to his life, "that real prosecutions come on the heels of such films being aired."