This is a troubling moment on many levels.
It represents yet another clear indication that America and its allies are facing a regional conflict in the Middle East.
It is a conflict in which they are protagonists, a conflict they are struggling to influence and a conflict which they have not contained.
It's moments like this which will come to mark turning points; a shifting of the dial, an attack which will force President Biden to respond.
The moment presents him with a complex range of challenges.
In an election year and with the polls against him, he faces a domestic conundrum: to double down hard in retaliation for the attack would be the natural response for the commander-in-chief.
But his probable political challenger, Donald Trump, is running with a narrative that Biden has pulled America into wars. Biden does not need this to escalate.
Geopolitically, the fact the attack reportedly took place inside Jordan, a close ally, is remarkable and troubling for Biden as well as for the Jordanian government.
Biden will probably feel compelled to send more troops into the region to further secure the US bases and act as greater deterrent. But that puts more of them in harm's way.
It will also add to internal tensions for Jordan where King Abdullah will not want to be seen to be such a visible supporter of America. Remember public opinion for America in the Arab world is extremely low following its unequivocal support for Israel's war in Gaza.
Since the 7 October Hamas attacks, there have been more than 150 strikes by Iran-backed militias in Syria and Iraq against US troops.
It's remarkable that none resulted in any fatalities, a fact that allowed President Biden not to feel compelled to escalate.
Last Sunday, two US Navy SEALs were confirmed to have died after they disappeared during a maritime operation to intercept weapons from Iran headed to Houthi fighters in Yemen. The clandestine, special forces nature of that mission allowed for a vague explanation and a vague response.
This latest attack is of a different order: three Americans dead and 34 injured.
For a president with so many challenges, domestic and global intertwined, the pressure is huge.