Maybe the most distasteful aspect of Donald Trump’s popularity among Republican primary voters has been his efforts to rehabilitate Russian President Vladimir Putin’s image in the United States.

One could contend that Trump’s flirtation with the authoritarian ruler in the Kremlin is founded in nothing deeper than the celebrity candidate’s penchant for reciprocating praise. After all, the Russian president called Trump a “talented” and “bright” person with whom the Kremlin could work, and Trump promptly responded with a display of veneration for Putin. Their mutual admiration is, however, a bit less superficial than that. It was Trump who initiated this fawning relationship with the new Tsar in Moscow after he repeatedly contended that Russian military adventurism and territorial acquisitions in Europe and the Middle East were somehow beneficial to American national interests. Trump has long claimed that he could “get along” with Putin and make mutually beneficial deals with the Russian president; deals which would presumably consist of ceding to Moscow virtually everything it wants with little or no regard for the geopolitical balance or Western concerns.

Trump’s faith in his own force of personality and his disregard for geopolitics or American grand strategy is part of his appeal. It would so complicate matters if the celebrity candidate’s followers were to demand of him concrete policy proposals and the details of a strategy through which they would be realized. Trump has, however, done more than simply cast himself in the mold of Putin, the tyrant. He has gone out of his way to apologize for the Russian president’s ghastly behavior.

“He kills journalists that don’t agree with him,” the exasperated morning show host Joe Scarborough exclaimed in one of his near-daily interviews with Trump. “I think our country does plenty of killing, also, Joe, so, you know,” the real estate mogul offered as a defense of both himself and Putin. Upon taking a few days to come up with something a bit more convincing, Trump confirmed that there is no defense of Putin’s record when he settled on the utterly unpersuasive contention: you’ll never prove it.

“Nobody has proven that he’s killed anyone,” Trump told ABC News. “He’s always denied it. It’s never been proven that he’s killed anybody.” The nation’s dubious fact-checking institutions immediately lent undue credence to Trump’s contention – it was, after all, literally true, but only for want of independent judicial institutions inside the Russian Federation.

It remains true that Putin’s complicity in the many crimes of which he is accused of facilitating has never been proven in a court. Unfortunately for those who doubt the Russian president’s direct involvement in the murder of his critics, the “you’ll never prove it” defense was rendered inoperative on Thursday. A British inquiry into the 2006 murder of the former Russian spy Alexander Litvinenko, who perished after suffering acute polonium poisoning, found that this crime was probably the work of Moscow’s FSB intelligence service. What’s more, Putin himself likely approved of the operation. “The two named assassins, Andrei Lugovoi and Dimitry Kovtun, remain in Russia, and the Russian government has rebuffed British attempts to secure their extradition,” the Washington Post reported. “Lugovoi, a former KGB officer, is now a member of the Russian parliament.”

Litvinenko is certainly not the only Russian who met an untimely end after proving to be a thorn in Putin’s side. In 2008, Sergei Magnitsky, a representative of a large post-Soviet capital management firm, was arrested and held without trial after providing details to the press about the corruption of the government. In detention, Magnitsky was beaten, tortured, denied medical care, and subsequently died. The Russian opposition leader Boris Nemtsov was shot to death within eyeshot of the Kremlin just one day before he was to lead Moscow in an anti-Putin protest. Somehow, the area’s ubiquitous security cameras failed to catch the perpetrators in the act, and the arrest months later of two Chechen men has failed to satisfy independent investigators. Anna Politkovskaya was just one of many journalists critical of Kremlin policy to meet an untimely end. She was shot to death in her apartment building on the Russian president’s birthday in 2006, and her murder horrified and galvanized Russia. In the end, Russian investigators dubbed her murder a conspiracy so vast that no fewer than five individuals were convicted of involvement in the crime after several trials. No Russian court has ever established who ordered her killing, but Russian investigators later implicated Putin critic and exiled oligarch Boris Berezovsky in her death – a ham-fisted attempt at obfuscation that could only be proffered in a totalitarian state in which dissent is virtually criminalized.

These are just a handful of the high profile individuals who died mysterious and premature deaths after running afoul of Vladimir Putin. For a figure who frustrates American national security interests abroad, exacerbated military and humanitarian crises in Europe in the Middle East, and has threatened on several occasions to compel the NATO military alliance to come to the defense of its members, Putin’s disregard for human rights and common norms of justice are the least of his offenses to Western sensibilities. But Trump and his followers seem to see only strength and high poll numbers in the Russian autocrat. Their efforts to restore the reputation of this threat to international security and human decency are the height of moral depravity. Now, a Western institution has provided some of the proof that Trump determined was all that prevented him from acknowledging the Russian president’s misdeeds. Don’t expect the celebrity presidential candidate to correct his misapprehension. His fans might mistake that kind of intellectual honesty for weakness.