President Donald Trump has shattered the limits of executive authority by ordering the summary executions of individuals he deems members of designated terrorist organisations. He has also tested the bounds of his presidential powers by creating a secret list of domestic terrorist organisations, established under National Security Presidential Memorandum 7 or NSPM-7.

Are Americans that the federal government deems to be members of domestic terrorist organisations subject to extrajudicial killings like those it claims are members of designated terrorist organisations? The White House, Justice Department and Department of War have, for more than a month, failed to answer this question.

Lawmakers and other government officials tell The Intercept that the pregnant silence by the Trump administration has become especially worrisome as the death toll mounts from attacks on alleged members of “designated terrorist organisations” in the Caribbean Sea and Pacific Ocean and as Trump himself makes ever more unhinged threats to imprison or execute his political adversaries.

In early September, The Intercept revealed that elite Special Operators killed the shipwrecked victims of a September 2 attack on a suspected drug smuggling boat. They have since struck more than 20 other vessels. The administration insists the attacks are permitted because the US is engaged in “non-international armed conflict” with “designated terrorist organisations” it refuses to name. Experts and lawmakers say these killings are outright murders – and that Trump could conceivably use similar lethal force inside the United States.

“The Trump Administration is trying to justify blowing small boats out of the water by arbitrarily calling them ‘designated terrorist organisations’ – a label not grounded in US statute nor international law, but in solely what Trump says,” Senator Tammy Duckworth, Democratic-Illinois), told The Intercept. “If Trump is using this justification to use military force on any individuals he chooses – without verified evidence or legal authorisation –  what’s stopping him from designating anyone within our own borders in a similar fashion and conducting lethal, militarised attacks against them? This illegal and dangerous misuse of lethal force should worry all Americans, and it can’t be accepted as normal.”

For almost a quarter century, the United States has been killing people – including American citizens, on occasion – around the world with drone strikes. Beginning as post-9/11 counterterrorism operations, these targeted killings in Afghanistan, Iraq, Somalia, Yemen and other nations relied on a flimsy legal rationale that consistently eroded respect for international law.

Details of these operations were kept secret from the American people, and civilian casualties were ignored, denied and covered up. The recent attacks on alleged drug boats lack even the rickety legal rationale of the drone wars, sparking fear that there is little to stop the US government from taking the unprecedented step of military action against those it deems terrorists within the nation’s borders.

The military has carried out 22 known attacks in the Caribbean Sea and eastern Pacific Ocean since September, killing at least 87 civilians. Last week, footage of the September 2 double-tap strike shown to select members of Congress ignited a firestorm. Trump announced, on camera, that he had “no problem” with releasing the video of the attack. This week, he denied ever saying it, in another example of his increasingly unbalanced behaviour.

“The public deserves to know how our government is justifying the cold-blooded murder of civilians as lawful and why it believes it can hand out get-out-of-jail-free cards to people committing these crimes,” said Jeffrey Stein, staff attorney with the American Civil Liberties Union’s National Security Project, on Tuesday, as the ACLU, the Centre for Constitutional Rights, and the New York Civil Liberties Union filed a federal lawsuit for the immediate release of a classified Justice Department’s opinion and other documents related to the attacks on boats. “The Trump administration must stop these illegal and immoral strikes, and officials who have carried them out must be held accountable.”

Since October, The Intercept has been asking if the White House would rule out conducting summary executions of members of the list “of any such groups or entities” designated as “domestic terrorist organisation[s]” under NSPM-7, without a response. Similar questions posed to the Justice and War departments have also been repeatedly ignored, despite both departments offering replies to myriad other queries. The Justice Department responded with a statement that did not answer the question. “Political violence has no place in this country, and this Department of Justice will investigate, identify, and root out any individual or violent extremist group attempting to commit or promote this heinous activity,” a spokesperson told The Intercept.

“The Trump administration should answer all questions about the terrorist lists,” Representative Ro Khanna (Democratic-California) told The Intercept. “The American people have a right to answers about who is on them and what that means for all of us.”

Rebecca Ingber, a former State Department lawyer, notes that while the designated terrorist organisation label as a targeting authority is “entirely manufactured,” the administration is relying on it to summarily execute people in the boat strikes, making their application of the terrorist label on the domestic front especially concerning.

“Many of us have warned that there seems to be no legal limiting principle to the Administration’s claims of authority to use force and to kill people,” Ingber, now a law professor at Cardozo Law School in New York, told The Intercept. “This is one of the many reasons it is so important that Congress push back on the President’s claim that he can simply label transporting drugs an armed attack on the United States and then claim the authority to summarily execute people on that basis.”

Last month, members of Congress spoke up against Trump’s increasingly authoritarian measures when a group of Democratic lawmakers posted a video on social media in which they reminded military personnel that they are required to disobey illegal orders. This led to a Trump tirade that made the White House’s failure to dismiss the possibility of summary executions of Americans even more worrisome.

“This is really bad,” the president wrote on Truth Social, “and Dangerous to our Country. Their words cannot be allowed to stand. SEDITIOUS BEHAVIOR FROM TRAITORS!!! LOCK THEM UP???” A follow-up post read: “SEDITIOUS BEHAVIOR, punishable by DEATH!” Trump also reposted a comment that said: “HANG THEM GEORGE WASHINGTON WOULD!!”

“What’s most telling is that the President considers it punishable by death for us to restate the law,” the six lawmakers – Senators Elissa Slotkin, Mark Kelly and Representatives Jason Crow, Chris Deluzio, Maggie Goodlander and Chrissy Houlahan – all of them former members of the armed forces or the intelligence community – replied in a joint statement. “Every American must unite and condemn the President’s calls for our murder and political violence.” Trump later claimed he did not call for the lawmakers’ executions.

For decades, Trump has called for violence against – including executions of – those he dislikes, including a group of Black and Latino boys were wrongly accused of raping a white woman jogger in New York’s Central Park in 1989; immigrants at the southern border, those who carry out hate crimes and mass shootings; demonstrators protesting the death of George Floyd; the chief suspect in the fatal shooting of a Trump supporter in Portland, Oregon; former chair of the Joint Chiefs General Mark Milley; and former Representative Liz Cheney. In August, Trump also called for “Capital punishment,” explaining: “If somebody kills somebody in the capital, Washington, we’re going to be seeking the death penalty.”

In January, immediately after being sworn in, Trump also signed an order to expand the death penalty, and Attorney General Pam Bondi has spent the year carrying out orders to put more Americans to death. Eleven states have executed 44 people since January, according to the Death Penalty Information Centre – the highest annual total in more than a decade.

White House spokesperson Taylor Rogers failed to answer questions about Trump’s history of threatening to kill people and his recent unhinged behaviour.

As Trump lobs threats at political foes and his administration seeks to put convicted and supposed criminals to death at home and abroad, NSPM-7 directs hundreds of thousands of federal officials to target US progressive groups and their donors as well as political activists who profess undefined anti-American, antifascist or anti-Christian sentiments.

• A Tell Media report / Adapted from The Intercept