President Donald Trump and his appointees have been accused of flouting courts in a third of the more than 160 lawsuits against the administration in which a judge has issued a substantive ruling, a Washington Post analysis has found, suggesting widespread noncompliance with America’s legal system.

Plaintiffs say Justice Department lawyers and the agencies they represent are snubbing rulings, providing false information, failing to turn over evidence, quietly working around court orders and inventing pretexts to carry out actions that have been blocked.

Judges appointed by presidents of both parties have often agreed. None have taken punitive action to try to force compliance, however, allowing the administration’s defiance of orders to go on for weeks or even months in some instances.

Outside legal analysts say courts typically are slow to begin contempt proceedings for noncompliance, especially while their rulings are under appeal. Judges also are likely to be concerned, analysts say, that the U.S. Marshals Service — whose director is appointed by the president — might not serve subpoenas or take recalcitrant government officials into custody if ordered to by the courts......

Legal experts said the pattern of conduct is unprecedented for any presidential administration and threatens to undermine the judiciary’s role as a check on an executive branch asserting vast powers that test the boundaries of the law and Constitution. Immigration cases have emerged as the biggest flash point, but the administration has also been repeatedly accused of failing to comply in lawsuits involving cuts to federal funding and the workforce.