When Was the Last Time There Wasn't Someone Holding a Sign Protesting Whatever in Front of the Whitehouse?

Thomas launched the anti-nuclear vigil outside the White House in Lafayette Square, Washington, D.C. on June 3, 1981.

In 2013, the Peace Vigil was disassembled while it was briefly left unattended. It was restored the same day.

2013?

Probably many days during Bidens run

Probably very early in the morning.