President John Quincy Adams, then a member of the House representing Massachusetts, became an outspoken critic of the Gag Rule. He thought it made a mockery of the First Amendment right to petition the government. He argued that all petitions“should be received, whether they come from the wealthiest individuals in the land, or whether they come from the poorest or lowest in character,” and he challenged the Gag Rule at every opportunity for years.

In one famous incident, he inquired whether the Gag Rule would prohibit him from presenting a petition by slaves. His colleagues from the South were outraged, calling for Adams to be censured or expelled for “gross contempt” of the House, and threatened to stage a walkout and “go home to their constituents.” They satisfied themselves with a resolution that slaves had no First Amendment rights to petition the government.

The Gag Rule’s opponents finally mustered the votes to repeal it in 1844. Ironically, it had contributed to the rising antislavery sentiment in the North. The lash of an antislavery petition or a floor speech is nothing compared with the lash of the whip. So the spectacle of proslavery representatives falling over themselves with outrage at even discussing slavery helped convince many in the North that the South really did have something to be ashamed and defensive about. The Gag Rule, and the blustering attempts to enforce it, made slaveowners look pathetic and malevolent.

So when Senator McConnell said of Senator Warren, “She was warned. She was given an explanation. Nevertheless, she persisted,” his words had an ugly echo. John Quincy Adams was warned and given explanations, but he persisted too. His point — and Ms. Warren’s — wasn’t that they didn’t know the rules, but that the rules were unjust and antidemocratic.