Iran’s Asymmetric Threat

By Raoul Heinrichs

Iran’s navy may not be a match for the U.S. on the high seas, but the Strait of Hormuz offers plenty of ways for it to make life tricky.

New Year in the Persian Gulf has opened in the usual atmosphere of scurrility, mistrust and competition. The Iranian nuclear crisis – already animated by economic and cyber warfare, an unrelenting diplomatic offensive, and a systematic program of sabotage, espionage and assassination – has, over the past month, incorporated yet another aspect: the specter of naval confrontation.

Iran is planning a new round of naval war games in February. These follow an earlier round, which unfolded against the backdrop of two unusually bold threats: the first, to close the Strait of Hormuz in response to the imposition of new sanctions; the second, to attack a U.S. aircraft carrier should it return to the Gulf.

Neither threat has so far been acted upon, of course, nor are they likely to be. As a number of analysts have noted, any attempt by Iran to disrupt the passage of oil out of the Gulf would be a largely self-defeating move, given its current economic fragility and abiding dependence on oil exports.

Rather, Iranian bellicosity is better understood as an attempt to shape expectations about its future behavior. In the rough-and-tumble world of international politics, a reputation for recklessness, even irrationality, can be a useful bargaining tool, as North Korean negotiating behavior attests. In particular, Iran is determined to drive up the risks of an attack on its territory, especially its nuclear facilities, by conveying the resolve and ability to respond with naval operations along a spectrum of intensity, from low level harassment of merchant shipping to the kind of hit-and-run attacks on U.S. naval platforms more commonly associated with Chinese strategy in the Western Pacific.

That questions remain about the credibility of these threats is cold comfort for U.S. military planners, though. For them, a preoccupation with capabilities rather than intentions, which can change, means they now confront a potentially asymmetric challenge in the Gulf at a time when they are trying to make deep cuts in the defense budget and reorient their strategic focus to Asia. Indeed, evidence suggests that Washington is taking Tehran’s threats seriously.

This is no surprise. By regional standards, the Iranian navy represents an atypically strong coastal force with a coherent force structure designed not to defeat a superior naval power so much as impose prohibitive costs on intervening in Iran’s southern air and maritime approaches. Built for sea denial, it comprises submarines, mines and fast attack craft armed with anti-ship cruise missiles. Each of these capabilities is cheap relative to the platforms against which they’re being fielded, and each places a disproportionate burden on the side seeking to defend against them. Submarines are hard to find; mines take a long time to clear; and Fast Attack Craft, especially when used in numbers and dispersed formations, are difficult to prevent closing to a range at which their missiles become a serious risk to even well protected ships.

The effects of this force are magnified by congenial naval geography. By contrast with the Western Pacific, with its oceanic expanses and concentric archipelagic chains, the Persian Gulf is a narrow body of water, making it conducive to offensive denial operations. It has one constricted entry point. This creates a funneling effect that allows Iranian forces to concentrate their firepower. Short distances make operations less surveillance intensive, and therefore less technologically demanding. They also compress the warning time available to an enemy defending against missile strikes, while long stretches of noisy coastal water create an ideal acoustic environment for lurking Iranian submarines. 

All of this makes Iran a tough competitor on its coastline, undoubtedly capable of raising the threshold for U.S. intervention in the Gulf. But it isn’t, ultimately, insurmountable. Iran’s naval potency diminishes sharply with distance and duration. Iran could mine the Strait, restrict commercial traffic and delay entry to U.S. forces while imposing moderate levels of risk in the meantime. However, its sclerotic command and control systems and lack of survivable land-based air-power betray an enduring inability to enforce a close or continuous blockade of the Straits, much less defeat the U.S. Navy in an open, protracted naval war.

No military balance is static, however, and the current extent of Iran’s naval inferiority isn’t necessarily immutable. Over the longer term, two shifts in the geopolitical landscape bode well for continued improvements to Iran’s prospects at sea. First, the emergence of a weak and divided Iraq in the place of a former existential rival is a geostrategic windfall. Historically, the greater salience of defending land borders has been a principal constraint on the development of naval power in countries with both coastlines and contestable continental frontiers – think China or France or Germany. For Iran, that may no longer be the case. With its western continental approaches now largely secure, and furthermore with the situation to it east improving as the U.S. backs out of Afghanistan, Tehran can channel a progressively greater proportion of is defense expenditure into its Navy.

Second, for China, cultivating Iran’s sea-denial capabilities is emerging as the most cost effective means of diluting U.S. primacy in the Gulf. This matters to Beijing because it is profoundly dependent on the sea-lines traversing the Gulf yet unable to reach or secure them with its own navy – and is therefore vulnerable to a distant U.S. blockade. There’s a reason, after all, why a good number of Iran’s anti-ship missiles are already stamped “Made in China.”
Raoul Heinrichs is Sir Arthur Tange Scholar at the Strategic and Defense Studies Centre, ANU, an editor at the Lowy Institute for International Policy, and Deputy Editor of Pnyx. This article was originally published on the Lowy Interpreter.
The Diplomat