Executive Orders is a techno-thriller novel, written by Tom Clancy and released on July 1, 1996. It picks up immediately where the final events of Debt of Honor (1994) left off, and features now-U.S. President Jack Ryan as he deals with foreign and domestic threats. The book is dedicated to former U.S. President Ronald Reagan, who helped launch Clancy's worldwide success as a novelist. The book debuted at number one on the New York Times bestseller list.

After a terrorist attack kills nearly every U.S. executive, legislative, and judicial figure, previously-confirmed Vice President Jack Ryan has been sworn in as President of the United States. As Ryan is left to represent the United States by himself, he must deal with multiple crises: reconstituting his own Cabinet, the House, the Senate, and the entire Supreme Court; a challenge to the legitimacy of his succession by former Vice President Ed Kealty, leading to press hazing; and a war brewing in the Middle East.

When the Iraqi president (implied to be Saddam Hussein) is assassinated by an Iranian deep-cover agent, Iranian leader Ayatollah Mahmoud Haji Daryaei takes advantage of the power vacuum by launching an unopposed invasion of Iraq and later uniting it with his country, calling the new entity the "United Islamic Republic" (UIR). Daryaei then secretly unleashes a master plan of "weakening" the United States through a series of terrorist attacks: a biological attack in the country using a weaponized strain of Ebola virus, a kidnapping attempt of Ryan's youngest daughter Katie, and an assassination attempt on the President himself by a Secret Service bodyguard who is an Iranian sleeper agent.

China and India secretly assist Daryaei, first by causing a diplomatic crisis between the Chinese mainland and Taiwan when a PLAAF aircraft "accidentally" shoots down a Taiwanese airliner. The incident pulls a U.S. Navy carrier group from the Indian Ocean to the South China Sea and allows the Indian Navy's carrier up to move undetected to the Strait of Hormuz, cutting off access to the only sea-bound pathway to the UIR and Saudi Arabia. Daryaei thinks that with the U.S. government and military overwhelmed by a multitude of crises, he is now free to invade Saudi Arabia and claim superpower status for the UIR.

The attack on Ryan's daughter as well as the assassination attempt on the President are swiftly averted by the FBI and Secret Service. However, the Ebola epidemic causes Ryan to declare martial law and enforce a travel ban to contain the virus. The epidemic later burns out due to the virus being so fragile that it cannot spread effectively. Meanwhile, CIA operatives John Clark and Domingo Chavez are tasked with investigating the origin of the virus in Africa, where they later discover Daryaei's involvement, connecting the puzzle of seemingly unrelated global crises. Ryan then deploys what is left of the United States military (the virus immobilized almost the entire military apparatus except for one fighter wing, two armored cavalry regiments, and one National Guard armor brigade that had been training at isolated Fort Irwin) to assist Saudi and Kuwaiti military forces in repelling a UIR invasion of Saudi Arabia.

The tide soon turns against the UIR, with its forces obliterated by the combined firepower of the United States, Saudi Arabia, and Kuwait. President Ryan had sent Clark and Chavez into Tehran, the de facto capital of the UIR, to target Daryaei with assistance from Russian intelligence. The Ayatollah is later killed in his residence by precision-guided munitions dropped from F-117 Nighthawks. Ryan then threatens to launch a tactical nuclear strike on Tehran unless those responsible for the attacks are immediately extradited to the U.S. to face charges, and the facility where the weaponized Ebola was cultured is neutralized. He announces a new foreign policy doctrine, the "Ryan Doctrine", under which the United States will hold personally accountable any foreign leader who orders attacks on U.S. citizens, territory, or possessions in the future.

Kealty's challenge to Ryan's legitimacy fails in court; due to the way Kealty's legal complaint was worded, the federal judge who hears the case inadvertently confirms that Ryan is the President. In the aftermath of the crisis, public appreciation of the unelected president grows.

The novel is composed of three major storylines. The first part is a realistic portrait about being the President of the United States, with "a near fetishistic pleasure out of detailing the ways in which [the chief executive] is robbed of his private life every minute of the day", according to novelist Marc Cerasini's essay on the book. The second part is about domestic critics and enemies — "venal politicos, fat cats, and corrupt media types", according to Publishers Weekly's review of the novel — that cause problems for President Ryan as he tries to rebuild the entire U.S. government with his centre-right politics and his grassroots American values. The third part features the United Islamic Republic's quest to become a superpower, which turns the novel into a "taut and harrowing" medical thriller that culminates in a military confrontation on land, sea, and air that is regarded as callback to Clancy's war novel Red Storm Rising (1986).