For all the attention Iran has received as of late, a significant development continues to be overlooked. Specifically, recent events have underscored that the three pillars of Iran’s long-standing deterrent-based military doctrine have become wasting assets in Tehran’s changing strategic environment. This factor is likely to be influential in shaping the regime’s continued debate over whether to cross the nuclear threshold. As Iranian policymakers lose confidence in their current deterrent capabilities, the strategic rationale for a nuclear arsenal will become increasingly apparent.
Since the end of its war with Iraq in 1988, Iran’s military doctrine has relied heavily on three capabilities to deter the country’s more powerful adversaries. The first pillar of this doctrine is the Iranian Revolutionary Guards Corps’ elite Quds Force, tasked with “exporting the revolution” abroad, usually through training and supporting proxy groups like Hezbollah in the tactics of unconventional warfare. Unconventional tactics allow Iran and its proxies to weaken its adversaries without openly confronting them. It also extends Iran's reach to areas like the Levant, Africa and even Latin America.
The second component of Iran’s military doctrine is its burgeoning ballistic missile arsenal, which is now believed to be the largest and most diverse in the region. Even without nuclear warheads, the increasingly sophisticated (pdf.) missiles are a valuable means of deterrence. Already they are capable of reaching U.S. bases in the region, all of Israel and parts of Europe; as early as 2015 they will also be able to reach the U.S. homeland, according to the U.S. Department of Defense.