He was best known for the controversy regarding his claims of military and combat service in the Vietnam War, and prior to that for his role in the so-called "Brokers of Death" arms case, a precursor to the Iran–Contra scandal in 1986.

[5] Northrop claimed that after graduating from The Citadel in May 1966, he joined the United States Army, serving almost three years, including a tour in South Vietnam and being badly wounded at the Battle of Lang Vei in February 1968.

[citation needed] Williams was convicted in February 1982 and in 1984, with the appeals exhausted, Northrop penned an op-ed for Penthouse magazine in which he covered the facts of the case.

In court hearings, Northrop[12] was described by The New York Times as "an American living in Tel Aviv" and by the US Government as "a high-ranking Israeli Intelligence official who was known to travel on 11 different passports.

"[13] Northrop was identified as the defendant that demanded from the putative Iranian buyers the release of four Israelis being held in Lebanon as a quid pro quo for the arms deal.

[18] According to the House October Surprise Task Force investigating allegations that officials tied to the campaign of Ronald Reagan successfully negotiated with the government of Iran for a solution to the Iran hostage crisis that would not occur until after the 1980 United States presidential election in order to prevent President Jimmy Carter from getting an electoral boost, Northrop's allegations of arms shipments had been cited as "part of the October surprise quid pro quo".

When Israeli civil and military officials examining his plans expressed skepticism over the viability of the project, with one referring to it as "summer dreams", Northrop threatened to take his plant to Holland where they would be able to "Sell planes to Arabs and Iran".

[7] A subsequent FOIA request initiated by the Associated Press in 2011 could also find no evidence of Northrop having any military service record whatsoever in the United States, after what was termed an "extensive" search of the National Archives and a check with the Federal Bureau of Investigation.

[7][24] When he was interviewed for Saigon to Jerusalem, Northrop gave a DD Form 214 supporting his service claims to the book's author, Eric Lee.

The document had numerous errors and discrepancies that, coupled with the fact that there is no corroboration of any military service in any official records, led many experts to judge it a forgery.

[30] When questioned by a reporter about the controversy over his military service claims and abrupt departure as the school's commandant, Northrop's quoted response was "I'm not running for president.

[22] Northrop's case has been cited by activists seeking to pass laws to criminalize false claims of military service at both the state and federal level, including in Nevada.