US defense analyst says nuclear use against Iran cannot be 100% ruled out

Capital Alpha defense analyst Byron Callan published a note saying the possibility that the United States would use a nuclear weapon against Iran cannot be 100% ruled out, while he doubts Washington would do so. The note, a sell-side assessment, came after President Trump said military action against Iran did not seem necessary, one day after he told CNN new bombing was highly unlikely if talks progressed. In the same period, Trump described minor US strikes on Qeshm Island; Iran's Revolutionary Guard reported tanker attacks, and a Houthi missile was reported to have damaged an Aramco tower.

Markets responded with the S&P closing up 2.4%, while Brent slid below $95, extending its biggest weekly drop since the Covid crash. Callan counted two carriers with roughly 96 combat aircraft, plus submarines and destroyers adding cruise-missile capacity; Trump said three carriers, but a Goldman analyst noted the USS Theodore Roosevelt was not expected before mid-November. The Israeli Air Force had the same number of combat aircraft and tankers as in February and March, and had rebuilt some but not all strike weapons. Basing for bombers and tankers remained uncertain. The note is an analyst assessment, not official policy.

The note reflects a pattern in which diplomacy and force are used as leverage: Trump's comments lowered oil and lifted equities, while reported strikes and tanker fires kept pressure on Gulf shipping. For Washington and Israel, air power can impose costs, but Callan's arithmetic suggests it cannot by itself change control of Iranian territory or guarantee protection for exposed forward aircraft. Iran's September 8 salvo at Muwaffaq Salti Air Base, which damaged aircraft despite more than 70 interceptors, illustrates that risk. The nuclear remark names a tail risk beyond ordinary war headlines.

The stakes reach beyond Tehran and Washington. Secretary Rubio said no breakthrough was in sight. Gulf exporters, tanker owners, insurers and airlines depend on routes through Hormuz and pipelines that have been reported hit or targeted. A wider conflict raises pressure on oil, freight and risk premiums, squeezing consumers and businesses even if diplomacy resumes later. The analyst note matters because it separates headline relief from operational reality: markets can move on a single statement, while military planners still face unresolved basing, stockpile and escalation questions.