Washington (CNN) Milk: It does the world's greatest deliberative body good.

As the second day of the impeachment trial of Donald Trump rolled on, the dairy drink made a small splash in the chamber of the US Senate.

Late in the afternoon on Wednesday, Arkansas Sen. Tom Cotton, a Republican, was seen downing two glasses at his desk, in between bites of chocolate. Directly across from Cotton's desk North Carolina GOP Sen. Richard Burr was sipping from his own glass of milk -- delivered by Senate pages -- as Democratic House managers delivered their opening arguments.

There was some talk that Sen. Elizabeth Warren had ordered a glass of milk on Tuesday afternoon. But the Democratic presidential candidate told reporters Wednesday that she had in fact snuck in some contraband yogurt.

Other than water, milk is the only beverage that, by tradition if not by rule, is allowed on the Senate floor.

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