Presumably in response to the latest Iranian militia inspired attack on the US embassy.
US Embassy attack in Iraq shows Trump's quandary in US-Iran escalation
It was rumoured that the latest Iranian inspired embassy attack was designed in part to shift focus from Iran's own internal civil unrest problems [ Initially started in response to US sanctions but almost certainly runs deeper]
With Brutal Crackdown, Iran Is Convulsed by Worst Unrest in 40 Years
Wouldn't be the first time a unpopular regime attacked another foreign power in order to shift domestic political focus from their own shortcomings.
We can be thankful that any American foreign policy shenanigans are not mediated by such blatant self interest.
Its not that the US president is any trouble domestically at present is it.
Nothing like a bit of sabre rattling for rallying the troops? Unfortunately its also how wars start