Lower-court judges have already blocked several Trump's policies including an asylum ban at the US-Mexico border.

While Trump's victories have ranged from universal injunctions to deportations, he's faced setbacks on both of those matters in addition to other policy areas.

The majority did not explain its decision in the brief, unsigned order. The court's three liberal justices opposed the order. Justice Sonia Sotomayor said the majority handed Trump the power to repeal laws passed by Congress “by firing all those necessary to carry them out.”

The Tuesday decision said that Trump's executive order directing agencies to develop workforce reduction plans is likely lawful.

Seven lawyers who spoke with Reuters cited a punishing workload and the need to defend policies that some felt were not legally justifiable among the key reasons for the wave of departures.