The conservative majority of the Supreme Court appears sympathetic to the Trump administration assertion that the president has the right to fire the heads of independent federal agencies in a case that could solidify Article Two executive branch powers.

The court heard more than two and a half hours of arguments Monday in Trump v. Slaughter, which challenged President Trump’s March firing of a commissioner of the Federal Trade Commission, Rebecca Slaughter. Ms. Slaughter, and the other Democrat on the panel, were informed via email that they were being removed from their positions.

The emails contained a message from Mr. Trump stating, “Your continued service on the FTC is inconsistent with my Administration’s priorities. Accordingly, I am removing you from office pursuant to my authority under Article II of the Constitution.”

Ms. Slaughter sued, claiming her firing was illegal because the message did not indicate that she was being fired for inefficiency, neglect of duty, or malfeasance in office, as required by Congress in the statute that created the agency. Lower courts agreed, and ordered her to be reinstated citing the 90-year-old Humphrey’s Executor v. United States precedent, which limits the president’s ability to fire officials at independent federal agencies except for cause.

But the Trump administration says the president’s constitutional powers are wrongly limited if he is blocked from firing members of the executive branch.

Solicitor General John Sauer argued the administration’s case, and called Humphrey’s a “decaying husk.” He added that the case was “grievously wrong when decided” and urged the justices to overturn it.

Justice Amy Coney Barrett agreed that the Humphrey’s precedence has been eroded over time. Justice Neil Gorsuch suggested it was time to rein in agencies carrying out both legislative and executive tasks.

Justice Brett Kavanaugh also appeared to accept most of the administration’s argument. “Broad delegations to unaccountable independent agencies raise enormous Constitutional and real world problems for individual liberties,” Justice Kavanaugh said.

But the liberal justices warned of a dire outcome if the court ruled in favor of the Trump administration.

“You’re asking us to destroy the structure of government,” Justice Sonia Sotomayor told Mr. Sauer. “Once you’re down this road, it’s a little bit hard to see how you stop,” Justice Elena Kagan added.

“The sky will not fall. In fact, our entire government will move toward accountability to the people,” Mr. Sauer countered.

The attorney representing Ms. Slaughter, Amit Agarwal, faced sharp questions by the conservative majority and admitted that control of the federal agencies needed to be in the president’s hands.

“If there are not sufficient mechanisms of adequate presidential supervision there could be a problem,” Mr. Agarwal stated, adding that the current system of independent agencies is working.

The Supreme Court has previously allowed Mr. Trump to fire members of the National Labor Relations Board and the Consumer Product Safety Commission. That has led to speculation that the court is leaning toward a decision in the president’s favor in Monday’s case.

Justice Kavanaugh did express “concerns” about the Slaughter case’s potential impact on the Federal Reserve. Mr. Trump has attempted to remove Lisa Cook from the Fed’s board of governors. The president says he was justified in her removal because of claims she committed mortgage fraud. Ms. Cook has denied the fraud claims and she has never been charged with any crime.

The Supreme Court is set to hear that case in January.

Justices have previously suggested that the Federal Reserve may have more independence than other agencies, so they could narrowly allow Ms. Slaughter’s firing to stand but stipulate the decision is not broad enough to cover the Fed.