A Legal Counteroffensive to Beat Back Trump’s Government Purges

A raft of new lawsuits contend that President Trump and Elon Musk are breaking the law to ransack the F.B.I. and other federal agencies. The courts will now decide.

Workers from across the federal government set off a legal counteroffensive against President Trump and Elon Musk on Tuesday, challenging the legality of efforts to raze their agencies, single them out publicly or push them out of their jobs.

The raft of lawsuits, filed by F.B.I. agents, public sector unions, representatives of older Americans and liberal-leaning legal groups, hinges on fine points of law that deal with matters ranging from the privacy of taxpayer data to intricacies of federal rule-making. But together, they amount to the opening shots in an emerging legal battle over the constitutional order, checks and balances and the founders’ vision of the separation of powers.

It will be up to the courts to decide whether the president has the power to not only direct the executive branch, but also to forcefully recast it in his own image. It may also be up to the judicial branch of government to find a way to ensure that its own decisions are enforced.

In short order on Tuesday, three government unions sued the U.S. Office of Personnel Management, or OPM — the federal government’s human resources division — to block an effort to convince roughly two million federal employees to resign from their jobs early.

Two groups of F.B.I. agents and bureau employees sued to block Mr. Trump from releasing the names of agents and staff members who participated in the investigations into the Capitol riot on Jan. 6, 2021, trying to head off what they fear is a looming purge.

Labor unions and a retirees’ group sued the Treasury Department to restrict access to sensitive Treasury systems that contain the private information of millions of Americans — and that the plaintiffs say may have already been compromised by Mr. Musk’s employees through what he has labeled the Department of Government Efficiency, or DOGE.