Fired FBI Director James Comey on Monday invited his million-plus Twitter followers to consider why President Donald Trump has yet to publicly criticize Russian President Vladimir Putin.

Comey proposed a so-called “thought experiment,” in which he asked his followers to compile a list of “all the public figures in this country and around the world the current president has criticized,” and challenged them to conjure up possible explanations as to why Putin is “missing from the list.”

“No responsible American should ever stop asking, “Why?” he added.

Thought experiment: Make a list of all the public figures in this country and around the world the current president has criticized. Ask yourself: “Why is Putin missing from the list?” No responsible American should ever stop asking, “Why?” — James Comey (@Comey) July 23, 2018

Comey’s tweet comes after White House press secretary Sarah Huckabee Sanders announced President Trump is “exploring the mechanisms,” to pull the security clearance of Obama-era intelligence officials, including the fired FBI Director, former bureau Deputy Andrew McCabe and ex-CIA Chief John Brennan.

The high-profile Deep Stater last week attacked President Trump’s joint press conference with Putin in Helsinki, Finland, accusing the president of siding with Russia over the U.S. on the issue of alleged election hacking. “This was the day an American president stood on foreign soil next to a murderous lying thug and refused to back his own country,” Comey said. “Patriots need to stand up and reject the behavior of this president.”

This was the day an American president stood on foreign soil next to a murderous lying thug and refused to back his own country. Patriots need to stand up and reject the behavior of this president. — James Comey (@Comey) July 16, 2018

Comey in April announced he was no longer a registered member of the Republican Party because they had “lost their way” after Donald Trump became president. “The Republican Party has left me and many others,” Comey said. “I can’t be associated with it.”

The Senate Select Committee on Intelligence in June 2017 released remarks prepared by Comey in which he confirmed he told President Trump on January 6, January 27, and March 30 that he was not personally under FBI investigation for collusion with Russia. Comey was relieved from his post in May of 2017, citing his mishandling of the Clinton email investigation.