US soldiers can disobey an illegal order coming from their superiors or the President.

The principle that US military personnel must obey lawful orders but are required to disobey illegal ones is well established in military law and doctrine. Multiple sources confirm that an order is considered illegal if it violates the Constitution, federal law, or established military regulations. Soldiers have a duty to refuse such orders to avoid criminal liability under the UCMJ. However, recognizing an illegal order can be challenging, especially in combat or chaotic situations, which complicates enforcement and compliance.

Key legal provisions include Article 90 and Article 92 of the UCMJ, which specify that charges for disobedience apply only to lawful orders. The obligation to disobey illegal orders extends even to orders issued by the President if those orders are unconstitutional or criminal. This is supported by legal analyses and court rulings emphasizing that following an illegal order is not a defense against prosecution.

Surveys indicate that a majority of US troops understand this duty to disobey illegal commands. Nonetheless, the practical application requires that the illegality be 'palpable' or clear beyond reasonable doubt, as vague or ambiguous orders may not trigger this duty. Legal experts also note the distinction between unlawful orders and those that may be questionable but not clearly illegal.

In summary, while US soldiers must obey lawful commands from superiors including the President, they are legally permitted and required to disobey orders that are manifestly illegal under military law and constitutional principles.