Then-Sen. James Jeffords, I-Vt.; then-Rep. Bernie Sanders, I-Vt.; and Sen. Patrick Leahy, D-Vt., drink glasses of milk in 1999. Senate rules during the impeachment trial of President Trump permit the consumption of milk on the chamber floor, a strange rule that has sparked a conversation on social media.

Then-Sen. James Jeffords, I-Vt.; then-Rep. Bernie Sanders, I-Vt.; and Sen. Patrick Leahy, D-Vt., drink glasses of milk in 1999. Senate rules during the impeachment trial of President Trump permit the consumption of milk on the chamber floor, a strange rule that has sparked a conversation on social media.