The strikes, which destroyed half of the kingdom’s oil production capacity, were claimed by Iran-backed Houthi rebels in Yemen.
On Sunday night Mr Trump said the US was “locked and loaded” and believed it knew who was truly behind the attack.
But Bernie Sanders, who is gunning for the Democratic nomination for president, tweeted: “Mr. Trump, the Constitution of the United States is perfectly clear. Only Congress—not the president—can declare war.
“And Congress will not give you the authority to start another disastrous war in the Middle East just because the brutal Saudi dictatorship told you to.”
In other news about his possible 2020 opponents, Elizabeth Warren was endorsed by the Working Families Party, an influential progressive group. She'll hold a rally in New York City this evening.
The president also spent some time defending Brett Kavanaugh amid a confusing new set of allegations concerning his behaviour in college, as well as his confirmation process.
As of now, all Democratic frontrunners are following in Ms Warren's lead to call for the Supreme Court Justice's impeachment - except Joe Biden, who simply requests that the matter is looked into.
Mr Trump, meanwhile, maintains that Mr Kavnaugh should sue his accusers.
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