Amid the fallout following the resignation of Michael Flynn as national security advisor to President Donald Trump, Stephen Colbert had some thoughts to share on the matter.

During the opening monologue of Tuesday night’s episode of The Late Show, the host slammed Flynn’s alleged communication with the Russian ambassador concerning U.S. sanctions imposed on Russia after the election, which now appears to be confirmed.

“Flynn called the Russian ambassador, discussed the sanctions, and allegedly signaled the Kremlin to expect a reprieve when Trump took office,” Colbert explained. “But he got caught because, turns out, we listen in on every phone call to the Russian ambassador. Who knew? Evidently not the national security adviser, you dummy!”

Watch the full clip below.

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Write to Megan McCluskey at megan.mccluskey@time.com.