Earlier this week, North Korea launched an intermediate range ballistic missile, dubbed the Hwasong-12, over Japanese territory – another in a string of recent provocations aimed at further enhancing the capabilities of its missile delivery systems.

In late July, Pyongyang conducted its first ever successful test of a longer range intercontinental ballistic missile with hopes of demonstrating to the United States and its East Asian allies – Japan and South Korea – the credibility of its growing nuclear deterrent. The regime of Kim Jong-un subsequently threatened that the next step was to land a series of missiles near the waters of Guam, a US territory with significant military assets, in the Pacific. There is also growing speculation that the North may conduct its sixth nuclear weapons test in the coming months, as tensions continue to boil with its confrontation with US President Donald Trump and his administration.

With all of these troubling incidents, there can be a tendency to dismiss the most recent test over Japan as another reckless action that – while provocative – should not be overplayed. This is especially true seeing as the incident took place alongside US-South Korea Ulchi Freedom Guardian war exercises – a time that is always tense and often results in provocations from Pyongyang. It is also true that the missile launch is not a “game-changer” and does not fundamentally alter long-standing deterrence and defensive readiness efforts between the US and its allies. Moreover, there continue to be no realistic and positive military options to definitively reduce or eliminate North Korean advances.

Despite this, this week’s test represents an acute escalation that demands a strong and united response from Washington and its allies. Arguably, this week’s test is the most significant provocation from North Korea, aimed at US allies, since its shelling of the South Korean island Yeonpyeong in 2010. The previous North Korean launches over the past few months have been “lofted” at a high altitude and fell short of Japan’s territory (although some did land in the exclusive economic zone waters near the country). This was a rational act of caution by the Kim regime, which wanted to avoid a potential altercation with or harsh response from Japan and its US ally. Indeed, the North had not tested a delivery system over Japan for seven years (its last test in the form of a satellite launch in 2009 drew outrage from Tokyo).

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But it appears that North Korea has now calculated that it can get away with tests over Japan – which can provide Pyongyang with additional valuable intelligence on the progression of its missile capabilities. Some analysts may be tempted to see Pyongyang’s action as a less aggressive move – considering its more provocative threat to Guam. After Trump hinted somewhat carelessly about a massive military response to such a move, the North perhaps opted to proceed more cautiously (while still saving political face) through the over flight of Japan. Indeed, Japan’s own newly minted foreign minister, Taro Kono, hinted at such a possibility this week.

A subdued retaliation may embolden North Korea to make more frequent tests over Japanese territory, a highly risky scenario that could result in a tragic accident and potential Japanese casualties.

Despite sharing a rational strategic objective not to escalate tensions into a potential conflict with North Korea, the US and its allies need to make it clear to the leadership in Pyongyang that they cannot establish a “new normal” by testing over Japan. A weak response will hurt regional deterrence efforts and undermine constant reassurances of US security guarantees to Japan and South Korea. Moreover, a subdued retaliation may embolden North Korea to make more frequent tests over Japanese territory, a highly risky scenario that could result in a tragic accident and potential Japanese casualties. Finally, a de facto acceptance of North Korea’s tests over Japan may force the hands of an anxious Tokyo to consider more closely the option to intercept any future missiles – despite the considerable risks involved.

How can the US and its allies proceed following the test? The reality is that, despite undesirable hard military options, Washington, Tokyo and Seoul do still possess several options in their toolkit and must develop a united sense of policy coherence to strengthen deterrence against Pyongyang and demonstrate that certain actions will not be tolerated.

First, all sides were right to press harder diplomatically through the United Nations Security Council. While there is room for tougher multilateral sanctions against the North – especially those that curb oil imports and penalise foreign banks that deal with the regime – such efforts are unlikely to succeed in any meaningful way as Russia and China, both permanent UNSC members with vetoes, are resistant to such ideas. Moreover, both Moscow and Beijing remain incensed with the US imposition of unilateral sanctions earlier this month on some Russian and Chinese entities that are linked to North Korea. This leaves the opening for stronger diplomatic efforts – including the potential for additional secondary sanctions – to punish those who do business with Pyongyang.

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A robust and frank engagement with China on the costs of its hesitancy to turn the screws on North Korea is also needed. But these diplomatic moves alone will not be sufficient. The US and its allies need to strengthen deterrence through demonstrating a firm and unambiguous signal of their resolve. In the medium-long term, this may involve the deployment of additional missile defence batteries in Japan and South Korea. In the short term, the US should consider brandishing its most sophisticated nuclear and conventional capabilities as a warning to the North. An example could be an overflight of the Korean Peninsula by some of its nuclear-capable bombers and the permanent repositioning of other (non-nuclear) hardware to South Korea and Japan. The US and its allies should also step-up covert activities to destabilise the North’s programmes and indicate the option to up the stakes via psychological warfare – a deep concern for the Kim regime. The risks of a weak response and muddling through are too great.

J Berkshire Miller is the director of the Council on International Policy and is a fellow on East Asia for the EastWest Institute.

The views expressed in this article are the author’s own and do not necessarily reflect Al Jazeera’s editorial policy.