How Trump shifted from opposing foreign wars to threatening war in Iran

The rationale to justify the US striking first has shifted from the country killing protesters to its developing weapons

As senior Democrats emerged from a classified briefing on Iran with the secretary of state, Marco Rubio, earlier this week, the leaders of the opposition delivered reserved, cryptic warnings of what may become the US's largest military intervention since the Iraq war.

This was not a line in the sand against a new war in the Middle East. Instead, Democrats targeted the opaque decision-making around Donald Trump - as well as his own unpredictable whims - that could guide the weightiest foreign-policy decision of his two terms in office.