After Frank's arrest, all of his friends in Washington gathered information with one goal in mind : catching the people who outed him, and destroy them before they could do more damage.
One of them quickly identified the obvious : it had to be Claire. She clearly hadn't always been comfortable with her husband's actions, and had decided to do the right thing and bring him down. Only her could have so easily known his weak points, going back to his early days as a young senator.
After a few other were convinced, they got to work and gathered everything they had on her : the affairs, the secret abortions, the relations between her NGO and Somalian arms dealers, the breaking of work ethics on a daily basis... it was only after everything had been sent to every news outlet in the country that they realized their mistake : how could someone so clearly self-interested and ready to do anything have brought down her own husband so close to his goal ?
mcmcsalot has been lynched. He was Claire Underwood, the Corrupt Politician (Town Vanilla) !