Closing Time: Assessing the Iranian Threat to the Strait of Hormuz

Abstract

How might Iran retaliate in the aftermath of a limited Israeli or U.S. strike? The most economically devastating of Iran's potential responses would be closure of the Strait of Hormuz. According to open-source order of battle data, as well as relevant analogies from military history and GIS maps, Iran does possess significant littoral warfare capabilities, including mines, antiship cruise missiles, and land-based air defense. If Iran were able to properly link these capabilities, it could halt or impede traffic in the Strait of Hormuz for a month or more. U.S. attempts to reopen the waterway likely would escalate rapidly into sustained, large-scale air and naval operations during which Iran could impose significant economic and military costs on the United States—even if Iranian operations were not successful in truly closing the strait. The aftermath of limited strikes on Iran would be complicated and costly, suggesting needed changes in U.S. force posture and energy policy.

Iran as a ‘pariah’ nuclear aspirant

“…Iran may retaliate against US interests in the Middle East, either directly or through its proxies, such as Hezbollah in Lebanon or the various Shia militias in Iraq. Direct retaliation by Iran is widely considered to be unlikely, however, given not only the USA's conventional superiority, but the political costs that Tehran would incur if, for example, it attempted to close the Strait of Hormuz in order to hamper oil supplies to the West (Talmadge 2008).…”

A Strait Comparison: Lessons Learned from the 1915 Dardanelles Campaign in the Context of a Strait of Hormuz Closure Event

“…A detailed analysis of this question was conducted by Talmadge using a scenario in which Iran was able to lay several hundred mines in the Strait and the Persian Gulf [27]. In her analysis, Talmadge assumes the U.S. considers its mine countermeasure (MGM) forces too vulnerable and scarce to use in a hostile environment, and so would instead wait to use them until it had essentially eliminated the threat from ASGMs.…”

“…Using mineclearance rates based on previous efforts in the Persian Gulf (e.g., Operation Candid Hammer), she concluded it would take between 28 and 40 days to adequately clear the minefields. Putting these two timelines together, she concluded overall that it could take 37 to 112 days for the U.S. to reopen the Strait under such a scenario [27]. Many of her assumptions regarding Iranian capabilities were subsequently disputed as giving the Iranians too much credit, but the disputer did not rule out completely the capability of Iran to threaten the Strait [28].…”

“…In a SoH closure, the U.S. would most certainly bring its considerable air power to bear in addition to its naval vessels, and the U.S. has technical methods for locating ASCM launchers [27,28] whereas the Allies had no such means of identifying the locations of the Turkish howitzers.…”

“…Obviously, the decision to try the latter, and later the former, did not work out well. In a SoH closure event, the U.S. might prefer to use its limited MCM assets in a later role, once it has first dealt with the Iranian ASCM threat, as Talmadge suggests [27]. However, political considerations may not afford the U.S. military the time for that option, and political/economic realities of a SoH closure might dictate the use of naval and air assets to deal with Iranian threats concurrently.…”