Kentucky Sen. Mitch McConnell, has a word of warning for Democrats: Don’t scrap the filibuster.

In a recent op-ed, the Senate majority leader writes that his Democratic colleagues will undermine the “constitutional order” if they use the nuclear option after the 2020 elections to end a senator’s ability to filibuster, or debate, legislation. (The term “nuclear option,” as used here, refers to instances in which a majority of senators use their power under the Constitution to ignore, circumvent, or change the Senate’s existing Standing Rules with a simple-majority vote in direct violation of those rules.) McConnell also predicts that Democrats will eventually come to regret scraping the filibuster.