A US aircraft carrier's passage through the Gulf is the latest demonstration of the superpower's enduring military presence in the West Asia aimed at reassuring allies, experts and officials say.
In a potent symbol of military might, the Abraham Lincoln carrier and its attendant warships cruised through the Strait of Hormuz this week.
The voyage came after United States President Donald Trump wrote in a tweet last month that “going into the Middle East is the worst decision ever”.
But since then, the US military has taken action to emphasise its long-standing presence in a region where the US has deep strategic interests.
It conducted massive trainings, announced the deployment of more troops and created a maritime coalition headquartered in Bahrain to protect shipping in the troubled Gulf waters.
The Abraham Lincoln's transit through the strait, which earlier this year was rocked by a string of attacks that Washington and its allies blame on Iran -- accusations Tehran firmly denies -- was the first for a US carrier since April.
“This show of force is part of a 'say-do' gap that is emerging between verbal US security guarantees in the region and actual American inaction,” said Andreas Krieg, a professor at King's College London.
“It is a desperate attempt to reassure allies in the Arabian Gulf.”
For more than seven decades, the United States has played an important role in the conflict-ridden region, serving in particular as a defender of Gulf monarchies against external threats, most notably Iran.
But Trump's tweet and his calls for Gulf leaders to pay for their security suggested a move to redefine the relationship -- born on an American battleship in 1945 when Saudi King Abdul Aziz bin Saud and US President Franklin D. Roosevelt first held talks.
There was further dismay last month when the US walked away from its Kurdish allies in Syria, opening a door for Turkey to launch a military campaign against the Kurds that was divisive even in Washington.
The apparent shift in US policy comes at a time of rising hostility with Iran.
Since May, tensions in the Gulf have increased with attacks against tankers, followed by drone and missile strikes on key Saudi oil facilities.
Iran was blamed, but denied involvement.
Despite the attacks on its ally and having one of its own drones shot down, the US has avoided equivalent retaliation.
Sending the carrier through Hormuz “is certainly supposed to send a message of defiance and strength after months of being humiliated by Iranian escalation”, said Krieg.
The strait, which separates Iran and the United Arab Emirates, is a chokepoint for a third of the world's seaborne oil. The shallow waterway is just 50 kilometres (30 miles) wide, making it a vulnerable shipping lane.