By Idrees Ali and Phil Stewart
WASHINGTON, July 22 (Reuters) - A Houthi threat to impose a naval blockade against Saudi Arabia in the Red Sea could significantly widen the Iran war and strain a U.S. military already focused on stopping Tehran's attacks across the region, current and former U.S. officials said.
Yemen's Iran-aligned Houthis said on Monday they would not allow ships to load or unload at Saudi ports, potentially blocking Saudi oil exports and choking off an additional 7% of global oil supply.
Saudi Arabia, which hosts U.S. forces, has not yet requested military assistance from Washington. But Trump suggested on Tuesday that a move by the group to obstruct shipping in the Red Sea — a vital corridor for global trade — could draw the United States in.
"If something like that happens, we'll take care of it. We've done that with the Houthis before," Trump told reporters on Tuesday.
For the U.S. military, it may not be so simple.
The Houthis have earned a reputation as hardened, nimble fighters who have successfully resisted earlier Saudi and U.S. bombing campaigns. Taking them on would mean stretching American resources already focused on fighting Iran and maintaining the United States' own blockade of Iranian ports in the Gulf.
"You're bifurcating your admittedly fairly robust resources in the region between two active fronts," said Jason Campbell, a former senior Pentagon official.
Campbell, now with the Middle East Institute, added that addressing the Red Sea threat could mean shifting U.S. warships from the Gulf closer to Yemen to allow the military to carry out operations against the militants and defend against Houthi missiles.
The possible entry of the Houthis into the conflict is another example of how the war - first pitched by Trump as a focused bombing campaign that would trigger Iran's capitulation - continues to evolve, worsening a political headache for the U.S. president.
And if U.S. Navy vessels and aircraft have to start shooting down Houthi drones and missiles, it could also worsen what experts have warned are diminished stockpiles of U.S. munitions and air defense interceptors.
The Pentagon did not respond to a request for comment.
RESILIENT HOUTHIS
The Houthis have been remarkably resilient through years of bombing by a Saudi-led Arab coalition, which tried unsuccessfully to crush the mountain fighters who are the de facto authority over much of Yemen, and more recent intense U.S. bombing campaigns.
"The Houthis have proven many times in the past that they have the ability and willingness to obstruct maritime traffic in the Red Sea and the Bab el-Mandeb strait," said Michael Mulroy, a former deputy assistant secretary of defense for the Middle East during Trump’s first term.
Under Joe Biden's administration, the United States conducted air strikes against Houthi targets in an effort to keep open the crucial Red Sea trading route. Trump intensified that effort last year, bombing the Houthis who had been firing at U.S. warships and commercial vessels off Yemen's coast.
Experts believe neither campaign ended the group's ability to threaten shipping.
But last year's two-month action did demand significant U.S. firepower, including two aircraft carriers, other warships, fighter jets and strategic aircraft such as the B-2 bombers.
While the U.S. military is the best funded in the world, it still faces resource constraints, officials say, with many of the systems likely needed for Yemen currently being used in the war in Iran.
"We're pretty busy already," one official said, noting that some warships had spent longer than usual at sea because of the high tempo of operations, first in the Caribbean and now in the Middle East.
Longer than expected deployments wear on service members. Ships eventually need to return to port for maintenance.
More than 20 U.S. Navy warships and hundreds of U.S. military aircraft are now operating in the Middle East. Additional forces are headed to the region to help with the Iran conflict, a second U.S. official said.
That could limit what is available for a conflict near Yemen, which officials say would require significant naval and aerial resources, and would divert U.S. intelligence resources, given the need to pinpoint Houthi capabilities that may have changed since last year.
Mark Cancian, a retired U.S. Marine officer at the Center for Strategic and International Studies, agreed that a second front in the Red Sea would stretch U.S. naval forces.
But, he added, the Houthis would face their own challenges getting resupplied, given the ongoing blockade of Iran, which has been the group's main supporter.
"The U.S. blockade is not 100% effective but it is highly effective. As a result, the Houthis may be hard pressed to continue a campaign for long," Cancian said.
(Reporting by Idrees Ali and Phil Stewart; Editing by Don Durfee and Kate Mayberry)
