John Mueller, a scholar of international relations at the Ohio State University, is a prominent nuclear skeptic. He makes three claims: (1) the nuclear intent and capability of terrorist groups such as Al Qaeda has been “fundamentally exaggerated;” (2) “the likelihood a terrorist group will come up with an atomic bomb seems to be vanishingly small;” and (3) policymakers are guilty of an “atomic obsession” that has led to “substantively counterproductive” policies premised on “worst case fantasies.” In his book Atomic Obsession: Nuclear Alarmism from Hiroshima to Al-Qaeda he argues that: "anxieties about terrorists obtaining nuclear weapons are essentially baseless: a host of practical and organizational difficulties make their likelihood of success almost vanishingly small".
Intelligence officials have pushed back, testifying before Congress that the inability to recognize the shifting modus oparandi of terrorist groups was part of the reason why members of Aum Shinrikyo, for example, were “not on anybody’s radar screen.” Matthew Bunn, associate professor at Harvard University's John F. Kennedy School of Government, argues that “Theft of HEU and plutonium is not a hypothetical worry, it is an ongoing reality." Almost all of the stolen HEU and plutonium that has been seized over the years had never been missed before it was seized. The IAEA Illicit Nuclear Trafficking Database notes 1,266 incidents reported by 99 countries over the last 12 years, including 18 incidents involving HEU or plutonium trafficking.
Keir Lieber and Daryl Press argue that despite the prominent U.S. focus on nuclear terrorism, "the fear of terrorist transfer [of nuclear weapons] seems greatly exaggerated... the dangers of a state giving nuclear weapons to terrorists have been overstated." A decade of terrorism statistics show a strong correlation between attack fatalities and the attribution of the attack, and Lieber and Press assert that "neither a terror group nor a state sponsor would remain anonymous after a nuclear terror attack." About 75 percent of attacks with 100 or more fatalities were traced to the culprits; also, 97 percent of attacks on U.S. soil or that of a major ally (resulting in 10 or more deaths) were attributed to the guilty party. Lieber and Press conclude that the lack of anonymity would deter a state from providing terrorist groups with nuclear weapons.
The use of HEU and plutonium in satellites has raised the concern that a sufficiently motivated rogue state could retrieve materials from a satellite crash (notably on land as occurred with Kosmos-954, Mars-96 and Fobos-Grunt) and then use these to supplement the yield of an already working nuclear device. This has been discussed recently in the UN and the Nuclear Emergency Search Team regularly consults with Roscosmos and NASA about satellite re-entries that may have contained such materials. As yet no parts were verifiably recovered from Mars 96 but recent Wikileaks releases suggest that one of the "cells" may have been recovered by mountain climbers in Chile.
RE: 'Thermo-nuclear war may breakout any moment: Trump is warned by China and North Korea