Donald Trump's sweeping assertion of power since returning to the White House is testing the U.S. constitutional system of checks and balances established in the 18th century as the president faces scant resistance from Congress and tensions with the federal judiciary escalate.

With a Congress controlled by Trump's fellow Republicans largely falling in line behind his agenda, federal judges often have emerged as the only constraint on the president's torrent of executive actions since his January inauguration.

His administration's degree of compliance with court orders impeding Trump's actions on foreign aid, federal spending, the firing of government workers and deportations carried out under a 1798 law historically used only in wartime has drawn scrutiny from federal judges presiding over those cases.

Trump this week responded to U.S. District Judge James Boasberg's order aimed at halting his administration's swift deportation of alleged Venezuelan gang members by calling for the judge to be impeached by Congress - a process that could lead to removal from the bench. Trump's statement drew a rebuke from U.S. Chief Justice John Roberts.

The nation's founders set up a system of government in the Constitution with three co-equal branches, a design intended to have the executive, legislative and judicial branches serve as a check on the power of the others.

Georgetown University law professor David Super said Trump "clearly is making a very aggressive move to expand presidential powers at the expense of the other two branches of government."

The Trump administration's remaking of the constitutional order is "happening in incremental steps," according to American University Washington College of Law professor Elizabeth Beske.

The Trump administration has argued that it is the judiciary, not the president, that is overreaching. Trump urged the Supreme Court on Thursday to limit the ability of federal judges to issue injunctions blocking his administration's actions nationwide.

"STOP NATIONWIDE INJUNCTIONS NOW, BEFORE IT IS TOO LATE," Trump wrote in a social media post. "If Justice Roberts and the United States Supreme Court do not fix this toxic and unprecedented situation IMMEDIATELY, our Country is in very serious trouble!"