Would the US allow its citizens to be attacked and killed by a foreign power and then cover up the facts?
It would - and it has.
On June 8th, 1967, the Israeli military attacked and attempted to sink the USS Liberty as she sailed under a US flag in international waters. Thirty-four US servicemen were killed and 171 injured by a well-coordinated, multi-wave assault which included the use of napalm.
The Israeli military called the attack a "tragic mistake" and then-President Lyndon Johnson agreed it was nothing more. Sailors who were aboard the ship were warned not to disclose the facts of what happened that day under penalty of court martial - or worse.
... since we are talking about false flag attacks so much today...