Putin’s response is now being carried out by Navalny’s jailers — complete with sleep deprivation, constant pain and denial of medical care, which several hundred Russian doctors described in an open letter last week as “deliberate torture.” “What is happening here is personal revenge,” wrote Yulia Navalnaya, the opposition leader’s wife. “This must be stopped immediately.”

Indeed, it must — and only one thing can stop it: direct personal intervention by the leaders of Western democracies to the man who is behind it. Torture and mistreatment are unacceptable in any case, even for actual criminals — let alone for a man who is imprisoned for his political beliefs. It’s a violation of every treaty and convention Russia has signed up to.

It is a matter of historical record that personal advocacy by Western leaders has helped save the lives (and freedom) of many political prisoners, both in Soviet times and in recent years. President Biden has made headlines by stating the truth when he described Putin as a “killer.” It’s now in his power to pick up the phone and ensure that the list of victims does not grow by another name.