Back when American politics was less competitive and less polarized, filibusters were rare. They were rare in part because the parties were ideologically diverse, which prevented the internal agreement that leads to coordinated and strategic obstruction, and in part because the minority party saw little chance of regaining power, which left it cautious about antagonizing the majority. But now that the disagreements between the parties run deep and control of the Senate teeters on a knife’s edge, the filibuster is a constant.
