US response President's options for military force are very limited

Donald Trump may not be "unafraid" to use military force against Iran, according to the White House, but the reality is that the US president has few to no options that could obviously help the country's protest movement, never mind the fact that the history of US intervention in the region has hardly been a success.

- Dan Sabbagh Defence and security editor

Emboldened by the seizure of the Venezuelan leader Nicolas Maduro after an operation that took months of planning, the US president talked up military intervention against the Iranian regime with no military pre-positioning having taken place.

In fact, the past few months have seen a drawing back, reducing military options further. The US has had no aircraft carriers deployed in the Middle East since October after two years of near-continuous deployment following the Hamas attack on Israel. It moved the USS Gerald R Ford to the Caribbean in the summer and the USS Nimitz to a port on the US west coast in the autumn.

It means any air or missile strikes against regime targets, and perhaps at the Iranian leader, Ayatollah Ali Khamenei, would probably have to come from or involve US and allied air bases in the Middle East. An alternative would be similar to June's long-range B-2 bombing mission against the underground Iranian nuclear site of Fordow, though this sort of attack against an urban site would appear to be dangerous overkill.

It means the US would have to ask permission to use bases in countries such as Qatar, Bahrain, Iraq, the UAE, Oman and Saudi Arabia (or perhaps even the UK's Akrotiri base in Cyprus) - and protect them and their host countries against retaliation. Even if such assets were not used by the US, Iranian leaders have threatened to strike US bases and ships if the country is attacked.