US threatens 'indefinite' blockade of Iran: How long can it last?

The United States has threatened to maintain an "indefinite" naval blockade of Iran's ports and impose new measures to isolate Tehran economically, as ceasefire negotiations between the two countries remain deadlocked.

However, US lawmakers raised alarms this week following reports of dire conditions on the flagship aircraft carrier USS Abraham Lincoln, including sailors attempting to jump overboard.

Despite President Donald Trump's claim that the US has "total control" over the Strait of Hormuz—a critical waterway Iran closed in early March shortly after war erupted—only a handful of vessels have managed to pass through this week.

"The repeated statements and posts by US officials that the Strait of Hormuz is no longer blocked do not change reality," Iran's PGSA said on X. "The Strait of Hormuz remains blocked and will not reopen until Iran's conditions are met."

What is the US saying?

On August 14, US Defense Secretary Pete Hegseth said the US military could maintain a naval presence in the region "indefinitely" to enforce a blockade of Iran's ports.

"The US Navy can sustain such a blockade indefinitely because we will rotate ships in and out, as we have done, and we will continue to do so," Hegseth told reporters during a trip to Panama.

Treasury Secretary Scott Bessent also said the US would impose new economic measures to pressure Iran. "Stay tuned for further announcements in the coming week because we will impose measures unprecedented in the history of economic isolation against a nation," Bessent said in a Newsmax interview. "It will be a combination of economic isolation the world has never seen, and a continued blockade at the Strait of Hormuz to prevent anything from entering or leaving Iranian ports."

Concerns over conditions on USS Abraham Lincoln

Questions have been raised about conditions on the USS Abraham Lincoln, the US Navy's flagship carrier conducting maritime security and blockade operations around the Strait of Hormuz.

US military publications Navy Times and Stars and Stripes, citing relatives of service members aboard, reported deteriorating mental health, morale issues, and cases of suicidal ideation. Navy Times interviewed Annabelle Loma, the wife of a sailor who said her husband attempted to jump overboard amid "severe exhaustion."

The reports prompted urgent inquiries from US lawmakers. In a letter to Hegseth, Democratic Senator Richard Blumenthal noted the carrier—which departed San Diego, California, in November with over 5,000 sailors and Marines—had been "continuously underway for nearly 7 months, a record," surpassing any previous US carrier deployment without a port call.

Blumenthal sounded alarms about declining mental health on board, shortages of essential supplies, water contamination, increased safety incidents, and disruptions to mail service, which delivers care packages from families.

"These reports need immediate attention, but they also raise a broader question: Can the Navy sustain the operational tempo being demanded of its carrier force, particularly as this administration repeatedly commits US forces to conflicts of its choosing and increasingly relies on carriers to sustain those operations?" Blumenthal wrote.

Senate Minority Leader Chuck Schumer called for Hegseth's removal over his handling of the carrier issue. "When Pete Hegseth was nominated, everyone knew he was utterly incompetent. Now our brave sailors are paying a terrible and unimaginable price," Schumer wrote on X. "Pete Hegseth must be fired immediately."

California lawmakers led by Representative Mike Levin also demanded Hegseth and Acting Navy Secretary Hung Cao explain the situation aboard the carrier. "Plans to rotate the USS Lincoln are insufficient. We need clear and honest information from the Department of Defense about the operational failures that led to the problems on the USS Lincoln to ensure this never happens again," the letter, signed by four lawmakers, stated.

Hegseth dismissed the reports, calling them "completely false."

Additionally, some media outlets, particularly Iranian media, reported that seven US Navy personnel were killed and several injured in a brawl on the USS Abraham Lincoln. US Central Command (CENTCOM) denied this, posting on X that the claim, as well as reports of suicidal ideation, were untrue. "The sailors and Marines of the Abraham Lincoln Carrier Strike Group remain resilient and steadfast after more than 260 days at sea. No service member has died on the carrier, and one sailor who went overboard on August 3 was quickly rescued safely."

How long can the US Navy hold out?

The Trump administration has said it will rotate ships in and out to ease pressure on naval forces in the Persian Gulf, with reports indicating the USS George Washington, currently in the Pacific, has begun heading toward the Middle East. However, experts say the ships in the Gulf have already been operating for too long without rest.

Harlan Ullman, a former senior naval officer and chairman of the Killowen Group, said the USS Abraham Lincoln requires periodic maintenance in port because it is a complex, modern ship. "The ship needs shoreside maintenance to keep advanced technology working over time. There are many things you can do at sea, but many others can only be done in port."

Ullman stressed that extended deployments like the Lincoln's nine-month stint "erode the ship's readiness the longer it stays at sea, and it lacks the ability to repair and sustain maintenance." He added that the Trump administration must prioritize naval readiness over politics.

Can Iran withstand the blockade?

The US hopes to cripple Iran's economy by maintaining the naval blockade. President Trump has signaled he prefers economic pressure on Tehran over a return to military operations, amid reports the US may be running low on defensive munitions—a claim the president denies.

The blockade has choked Tehran's most critical revenue source: crude oil. Iran is estimated to have lost at least $6 billion in oil revenue since the blockade began on April 13, which Tehran calls "an act of piracy."

However, experts say there are reasons Iran is in a stronger position than the US claims. Ali Vaez, deputy director of the Middle East and North Africa program at the International Crisis Group, said: "Iran can raise the stakes by targeting US naval assets or pushing the Houthis to tighten the noose around regional energy exports. Tehran's calculation is that in any game of chicken with Washington, the US blinks first—and they see little reason to believe it will be different this time."

Iran's control of the Strait of Hormuz is a major lever, experts note. Iran has repeatedly said it will not reopen the critical waterway until the US naval blockade is lifted, sanctions are removed, and its assets are released.

On August 14, IRGC Navy Commander Rear Admiral Ali Azmaei declared: "We have complete and decisive control over all movements. No movement in this strait goes unnoticed by IRGC Navy fighters."

Mostafa Khoshcheshm, a professor at Tehran University of Applied Science and Technology, said Iran views itself as fighting an economic, not military, war with the US. "Iran knows that to defeat the US, it must use asymmetric warfare, and in this economic war, the Strait of Hormuz is paramount." Iran hopes the US will "admit defeat and leave the region."

Another angle is the economic pressure Iran is exerting on neighboring countries by targeting US military assets stationed there, as well as infrastructure and energy facilities. Mehran Kamrava, professor of government at Georgetown University in Qatar, told Al Jazeera: "What we are seeing is the Iranians trying to apply economic pressure on neighboring states, particularly countries like Qatar, UAE, Saudi Arabia, and Kuwait, to pressure the US into negotiating with Iran."

Kamrava was skeptical that US economic pressure on Iran would prove effective, especially as Iran's leadership faces no domestic political pressure like the Trump administration. "Tehran is under immense economic pressure, but we must remember that Iran's political system is essentially an authoritarian one. The decision-makers are not directly concerned about the circumstances of the middle class. They want to retain power. So I'm not sure this tactic will work at this point."