Democrats have made clear that if they win the presidency and Congress in November, they will attempt to take over the Supreme Court as well. Shortly after ending his re-election campaign, President Biden put forth a package of high-court “reforms,” including term limits and a “binding” ethics code designed to infringe on judicial authority. Kamala Harris quickly signed on, and Majority Leader Chuck Schumer has made clear that bringing the justices to heel is a top priority. Democrats proclaim their devotion to democratic institutions, but their plan for the court is an assault on America’s basic constitutional structure. The Framers envisioned a judiciary operating with independence from influences by the political branches. Democratic “reform” proposals are designed to change the composition of the court or, failing that, to influence the justices by turning up the political heat, as President Franklin D. Roosevelt achieved with his failed 1937 court-packing plan. Now as then, the court stands between a Democratic administration and its ambitions. The reformers’ beef is precisely that the court is doing its job by enforcing constitutional and statutory constraints on the powers of Congress and the executive branch. Roosevelt sought to shrug off limits on the federal government’s reach. What’s hamstrung the Obama and Biden administrations is the separation of powers among the branches. President Obama saw his signature climate initiative, the Clean Power Plan, stayed by the court, which later ruled that it usurped Congress’s lawmaking power. The Biden administration repeatedly skirted Congress to enact major policies by executive fiat, only for the courts to enjoin and strike them down. That includes the employer vaccine mandate, the eviction moratorium and the student-loan forgiveness plan. That increasingly muscular exercises of executive power have accompanied the left’s ascendance in the Democratic Party coalition is no coincidence. The legislative process entails compromise and moderation, which typically cuts against radical goals.

Then there’s the progressive drive for hands-on administration of the national economy by “expert” agencies empowered to make, enforce and adjudicate the laws. The Supreme Court has stood as a bulwark against the combination of powers that James Madison pronounced “the very definition of tyranny.”

That explains the Democratic Party’s attacks on the court. The New York Times’s Jamelle Bouie recently praised Mr. Biden for identifying the court as the “major obstacle to the party’s ability” to carry out its agenda and commended the president’s “willingness to challenge the Supreme Court as a political entity.” That explains the ginned-up “ethics” controversies: The aim is to discredit the court, as has become the norm in political warfare.

What Mr. Biden, Ms. Harris, Mr. Schumer and their party are attempting to do is wrong and dangerous. They aim to destroy a branch of federal government. For faithfully carrying out its role, the court faces an unprecedented attack on its independence, beyond even Roosevelt’s threats. Unlike then, however, almost every Democratic lawmaker and official marches in lockstep, and the media, which were skeptical of Roosevelt’s plan, march with them.

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