Bob Woodward’s explosive new book on US President Donald Trump has sent military analysts worldwide scrambling over a boast Trump made to the veteran Washington journalist of a potentially nuclear weapons system that “nobody’s ever had.” Trump appeared to disclose top-secret defence information in one of 17 on-the-record interviews he gave for Woodward’s just-released book Rage , about the US leader. Trump says his government has built a weapon system that no one else, not even the leaders of Russia and China, knows about, and seems to say it is “nuclear”. Such a revelation, if true, could shake up great power politics and inflame the arms race. But the 54-word audio interview clip from December 5, 2019 that Woodward released with the book obfuscates as much as it exposes, mainly because when saying “nuclear” Trump breaks off mid-word, as if he is correcting himself, and then changes to “a weapons system”. “But I have built a nucle-, a weap-, I have built a weapons system, weapons system, that nobody’s ever had in this country before,” Trump said. “We have stuff that you haven’t even seen or heard about. We have stuff that Putin and Xi have never heard about before. There’s nobody. What we have is incredible.” Woodward said he had confirmed separately with sources that the United States indeed has a new secret weapon, but did not say whether it was nuclear or not. ‘Deadly stuff’: Trump knew virus threat but played down risk But arms experts say they are not sure what Trump was talking about, or whether it was one of the hollow boasts he is known for. Hans Kristensen, director of the Nuclear Information Project at the Federation of American Scientists, says it could be a low-yield nuclear warhead, the W76-2, that was deployed for the first time on a nuclear submarine in January, a month after Trump mentioned it to Woodward. Cheryl Rofer, another nuclear scientist, says it could refer to an all-new warhead just under development, the W93, first revealed by the Pentagon earlier this year. Others think Trump did not mean nuclear at all. The boast came in the same period that Russia and China had appeared to take a lead in the development of hypersonic glide vehicles, missiles currently almost impossible to defend against. Three weeks after Trump gave the interview, Russia announced its first Avangard hypersonics had been put into service. On January 8 Trump declared the US was also building hypersonics, and in the following months he branded it the “super-duper missile.” “We have one 17 times (the speed of sound). And it’s just gotten the go-ahead … Fastest in the world by a factor of almost three,” he said on May 15. Arms control expert Jeffrey Lewis said Trump’s language in the Woodward interview “really mirrors” his comments on the “super duper missile”. Book reveals how Kim Jong-un wooed Trump with flattery-filled letters But others are not sure Trump was not making it all up. “It’s always risky to parse only a few words from Trump,” Rofer said. “He misunderstands so much and lies so much. ‘Nobody’s ever had’ is one of his trademark brags.” Asked about Trump’s comment, the Pentagon demurred. “I’ll have to refer you to the White House to clarify what the president meant in his remarks,” said a spokesperson, Lieutenant Colonel Robert Carver.