So like the Trump administration, systematically undermining American democracy in favor of Putin, and sending violent crowds of drooling mouth breathing batshit crazy white supremacist insurrectionists breaking and entering into sacred government buildings, beating the living daylights out of police and stealing their equipment as they lay crying in pain on the ground, driving them to commit suicide, smearing shit on the walls and floors of Congress, proudly parading Racist Confederate Loser Battle Flags around the Capitol, stealing and vandalizing government property, shouting out their support for Trump while correctly claiming and proudly posting to social media that they are acting on his behalf and at his command, and trying to capture and murder American politicians including the Vice President himself.

A fifth column is a group of embedded traitors.

I am not sure the word is suitably used here.

Franco (loosely). "We'll be marching towards Madrid in four columns. The fifth column is already in the city".

As in Francisco Franco? Thank you for the definition and some bonus etymology!

Yep same guy, during spanish civil war in the 1930s