How NK's crossing of 'orange line' challenges U.S. 'red line'

By Lee Jong-eun

Last week, North Korea fired an intermediate-range ballistic missile (IRBM) over Japan in what it claims to be part of "tactical nuclear drills." The missile was reportedly a version of the Hwasong-12, similar to the North's missile fired in 2017. The missile flew 4,600 kilometers, flying briefly over the northern prefectures of Japan before falling eventually into the Pacific Ocean to the east of Japan.

The United States, Japan, and South Korea responded with more robust military measures than they did toward other North Korean missile tests conducted this year. On the day of the missile launch, the U.S. and South Korean air forces conducted a joint exercise in the West Sea. The U.S. aircraft carrier USS Ronald Reagan, which participated in the trilateral naval exercise in September, returned to the Korean Peninsula to conduct another naval drill with allied navies.

The U.S. has long warned North Korea not to cross the "red line" by testing an intercontinental ballistic missile (ICBM) capable of reaching the U.S. mainland. Despite predictions that the North will soon conduct an ICBM or a nuclear test, the regime has refrained from testing the U.S. warning for the past five years. The Biden administration, despite rhetorical condemnations of the North's other missile tests, has also not taken significant retaliatory actions against the regime.

A tacit stalemate has strategic benefits for the U.S. in containing the security threats in East Asia. With the outbreak of the Russia-Ukraine War this year, and U.S.-China tensions over issues of Taiwan and supply chains, U.S. policymakers face multiple constraints in confronting North Korea.

Rather than risking escalation, the Biden administration's North Korea policy for the past two years has been characterized largely as low-key responses toward the regime's relatively low-key threats, combined with warnings if the latter conducts an ICBM or a nuclear test. While a form of threat, the drawing of a "red line" has a paradoxical counter-message: it implicitly tolerates behaviors that do not explicitly violate the line.

The two challenges to red-line warnings are credibility and inflexibility. First, how credible is the warning that there will be severe retaliation if the line is crossed? The target of the warning might engage in provocations to probe the credibility. Observing no significant retaliation, the target might assume that the consequence for violation would not be as severe as warned. Second, even if the target does not explicitly cross the red line, the target's provocations could cause significant problems and costs. The risk of tying the retaliation only to the explicit violation is that it could constrain the enforcer's behavior more than the violator's.

The North's latest missile test highlights these challenges for the U.S. alliance in East Asia. Advancing from previous short-range missile tests, North Korea launched a ballistic missile with a range covering Japan and Guam. Even if the U.S. is inclined to maintain restraint as no ICBM has yet been tested, South Korea and Japan perceive significant threats from North Korea's missile provocations and demand a robust counter-response from their superpower ally. Despite the U.S. strategic interest in mitigating conflict with the North unless directly threatened, the security vulnerability of its allies places the U.S. in a strategic dilemma.

Furthermore, how the U.S. responds to North Korea's provocations influences the red line's credibility. In 2017, when President Trump threatened to counter North Korea's provocations with "fire and fury," his threats were taken seriously due to widespread perceptions of Trump's unpredictability. Today, the Biden administration faces skepticism on whether the U.S. would impose retaliatory measures even if North Korea resumes ICBM and nuclear tests.

The U.S. responded to the North's recent IRBM test with a series of military exercises together with allies to dispel such doubts. However, doubts remain on whether such responses are permanent commitments: would the U.S. deploy its carrier group to respond to the North's future IRBM tests? The limitation of relying on the "red line" as deterrence is that it leaves unclear what responses will be taken toward provocations that may not cross the line but still poses significant strategic threats.

In response to multiple levels of North Korea's provocations, establishing multiple levels of countermeasures would be a more effective deterrence strategy. For example, depending on the range of the individual missile tests, the specific scale of counter-response measures could be operationalized and communicated to the North. A distinct category of "orange-line provocations" could be established to distinguish levels of provocations, such as the IRBMs, that causes significant risks to the U.S. regional alliance and require more robust responses than lower levels of provocations. Ultimately, the U.S.' resolve to implement operational protocols according to the defined levels of provocations would enhance the credibility of the measures reserved for the red-line violations.

Critics might worry that establishing specific levels of countermeasures could impose constraints on U.S. foreign policy and risk escalating conflict with North Korea. Though valid concerns, critics should consider the strategic benefit of reassuring U.S. allies of the predictable scope of U.S. security commitment; if the U.S. government commits to graduated levels of countermeasures toward the North's provocation.

The risk from signaling operational clarity toward North Korea should be weighed together with the risk from signaling operational ambiguity, which could cause the North to underestimate or overestimate U.S. intention. A clearer distinction between the countermeasures toward orange- and red-level provocations could better signal the risk of escalation to North Korea and help achieve restraints in the latter's provocations.

The geopolitical reality of the Korean Peninsula is that coexisting with a nuclear North Korea is unavoidable, as achieving denuclearization would be a long-term process. However, in engaging with the nuclear North, the U.S. alliance should ensure that North Korea also recognizes the risk of nuclear and missile provocations so that diplomacy can be conducted with mutual restraint and risk management.

Lee Jong-eun (jl4375a@student.american.edu), a Ph.D. candidate, is an adjunct faculty at the American University School of International Service. Prior to this, he has served as a South Korean Air Force intelligence officer. His research specialty includes U.S. foreign policy, South Korean politics and foreign policy, alliance management and East Asian regional security.