President Donald Trump will ask the Supreme Court to allow him to fire the head of a government ethics watchdog agency in the first appeal from his litigious second term to reach the nation’s highest court.

At the center of the appeal is Hampton Dellinger, who leads the Office of Special Counsel and whom Trump fired this month despite protections enacted by Congress that require an administration to show cause before dismissing someone from the post before their five-year term has ended.

A federal district court temporarily blocked Dellinger’s dismissal while it considers his case, and the US Circuit Court of Appeals for the DC Circuit late Saturday declined to overrule that decision. The Justice Department prepared its appeal to the Supreme Court within hours of that decision.

Is there anyone in government Trump can’t fire? Why Humphrey’s Executor may be in peril at the Supreme Court

The Justice Department described the district court’s ruling as an “unprecedented assault on the separation of powers,” according to a copy of the appeal obtained by CNN.

“Until now, as far as we are aware, no court in American history has wielded an injunction to force the president to retain an agency head whom the president believes should not be entrusted with executive power and to prevent the president from relying on his preferred replacement,” the administration asserts in its appeal.

On the one hand, the case carries enormous significance. It is the first appeal of what will likely be many to reach the high court challenging Trump’s whirlwind of executive actions as he has sought to consolidate power in the executive branch during the opening weeks of his second term. In other contexts, several conservative Supreme Court justices have indicated they might support Trump’s broader goal of having greater control over executive branch employees.

But on the other hand, the preliminary posture of the case presents a major challenge to the Department of Justice. Temporary restraining orders like the one issued in this case generally are not appealable. They are usually put in place for a few weeks at most to give lower courts time to review the legal arguments presented by both sides.

Even if the Supreme Court rejects the Trump administration at this stage, the court will almost certainly get another crack at it in a few months. It is at least possible that some of the justices will write short opinions explaining their position on the broader merits questions at issue in Dellinger’s case. Either way, the Supreme Court could move relatively quickly on the emergency appeal, likely providing some indication about how it will handle the request early this week.

The Office of Special Counsel — which is distinct from the special counsels appointed to oversee politically sensitive Justice Department investigations — handles allegations of whistleblower retaliation and is an independent agency created by Congress.

In a 2-1 decision on Saturday night, the US Circuit Court of Appeals for the DC Circuit said the temporary order allowing Dellinger to temporarily remain in the post was not appealable. Reviewing such an order, the court said, “would be inconsistent with governing legal standards and ill-advised.”

Granting a stay of a temporary restraining order, the court ruled, “would set a problematic precedent. If we were to accept the proposition that a party’s bare assertion of ‘extraordinary harm’ for fourteen days can render a TRO appealable, many litigants subject to TROs would be encouraged to appeal them and to seek a stay.”

Two Biden appointees, Circuit Judges J. Michelle Childs and Florence Pan, voted to dismiss the Trump administration’s request for a stay. US Circuit Judge Gregory Katsas, a Trump nominee, said he would have granted the government’s request.

Dellinger’s lawsuit is one of at least three brought by officials fired by Trump that test a president’s power to oust heads of independent agencies.

The lawsuits rely in part on a 1935 Supreme Court precedent, Humphrey’s Executor v. United States, that allowed Congress to include for-cause protections for members on independent federal agency boards. Several conservative justices have signaled an uneasiness with the decision in recent years, and the Department of Justice under Trump has said it believes the protections are unconstitutional. (CNN)