If the international community routinely condemns the pursuit of strategic weapons such as ballistic missiles, not to mention the nuclear warheads they can carry, then why do so many countries insist on pursuing them? It's a question worth asking, and to answer it, we need only look at Iran and North Korea, relatively weak states that have both been pretty provocative of late.
Early this morning, Iran launched two ballistic missiles — its second launch in two days — and in doing so raised the question of whether the West would reapply sanctions against it. Separately, North Korea announced today that it had successfully miniaturized a nuclear warhead, something that would, in theory, enable the country to finally deliver its payloads. While different in scale, these kinds of actions are undertaken for one reason alone: military necessity.
Iran is opening its economy, thanks in part to the implementation of the nuclear deal and the electoral victory of the pragmatic conservative coalition of President Hassan Rouhani. But for Iranian policymakers, neither one of these things actually makes the country more secure. Maintaining and improving its ballistic missiles does. The ballistic missile program touches on the country's core security issue of deterrence, which actually transcends politics.
No matter who is in charge in Iran, the government will need to hedge against rival states including Saudi Arabia, Israel and, to a lesser extent, Turkey. Saudi Arabia is particularly alarming for Iran because of its geographic proximity, robust alliance within the Gulf Cooperation Council and years of sanctions-free spending on top-end Western military platforms. Tehran cannot realistically expect to win a conventional military conflict with Saudi Arabia, so it must rely on asymmetric responses — namely, ballistic missiles — to deter Riyadh's actions.
Notably, ballistic missiles are only tangentially related to Iran's nuclear program. A conventional ballistic missile program still has strategic value without nuclear weapons. This is why the sanctions associated with Iran's ballistic missile program are different from the sanctions related to the nuclear deal — and why Iran is compelled to continue to pursue them.
In North Korea, the pursuit of nuclear weapons likewise stems from insecurity. Leaders in Pyongyang believe a U.S.-led alliance, whose military capability far exceeds their own, is dead set on removing them from power. And though their concerns may appear irrational, it is important to bear in mind that the United States has brought down governments in Afghanistan, Iraq and Libya in the past 12 years alone. And in no instance did the old ruling class survive and wield actual power.
With those concerns in mind, North Korea sought to mitigate the threat its leaders thought the United States posed. At one point, North Korea appeared to believe it could trade its nuclear capability for a long-term security guarantee. But as the years dragged on, the North Koreans developed an increasing sense that American hostility was implacable. Rightly or wrongly, North Korea now equates the possession of a viable nuclear weapon to the survival of the regime itself. And it is willing to endure hideous costs to survive. Even the recent U.N. sanctions brought against Pyongyang — the toughest sanctions in history — will not be enough to change the country's mind. To forgo a nuclear program as Iraq did would be to remain vulnerable to invasion. To cooperate with the international community, as Libyan leader Moammar Gadhafi did, would be to consign themselves to death.
Of course, the strategies of Iran and North Korea differ fundamentally. Iran is willing to curb its nuclear program in exchange for concessions; that it probably would not even be able to weaponize a device without incurring a pre-emptive military strike certainly informed its decision. North Korea doubled down on its program, creating just enough ambiguity to deter a pre-emptive strike. But the motivation behind the strategy — the preservation of national security — is the same. Both countries will therefore continue to test their weapons and make sure their neighbors see them do it.