Progress towards a nuclear deal between the US and Iran remains murky with all-out war still a potential outcome.  

A third round of indirect talks has just concluded in Geneva, with further discussions to take place in Vienna next week.  

The pressure's on Iran, with the US deploying its biggest military build-up to the Middle East in decades. 

US Correspondent Richard Arnold told Mike Hosking the debate about whether an attack is viable is spilling out into the public now. 

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