Adam Mount is a senior fellow and director of the Defense Posture Project at the Federation of American Scientists. He is the co-director of the FAS International Study Group on North Korea Policy, a group of fourteen experts that proposed a consensus strategy to manage a nuclear-armed North Korea. The opinions expressed in this commentary are his.

(CNN) North Korea has carried out the latest in an escalating series remarkably of advanced missile tests . Throughout the year, Pyongyang has been abundantly clear that it will not wait around while negotiations stagnate but will continue to ratchet up pressure on the Trump administration to reach a deal.

Kim Jong Un's regime's latest step is this week's test of a new medium-range missile, its first at that range since before negotiations with the US started.

For most of the last year, talks have been a stalled charade that provides cover for Pyongyang's advancements. Now they appear headed for a dramatic collapse.

With the US President and Secretary of State consumed by an impeachment inquiry and domestic scandal, the best we can hope for is that the administration presses pause on North Korea.

Uptick in tests

In late 2017 , North Korea successfully tested a large intercontinental ballistic missile and then voluntarily refrained from testing for almost a year and a half while negotiations were underway. After US-North Korean talks failed to produce any agreement of substance, Kim warned in April that the United States had until "the end of this year" to make a new offer.

In July , a North Korean Foreign Ministry spokesman declared that the United States was "unilaterally reneging on its commitments" and that the regime was "gradually losing our justification to follow through on the commitments we made with the US."

Beginning in May, Pyongyang carried out 18 tests of a new generation of remarkably advanced weaponry: two types of short-range ballistic missile and two new large-caliber rocket artillery systems.

The most alarming of these four is the KN23, a short-range missile capable of maneuvering in flight along a deliberately depressed flight path. The regime's statements announcing the launches imply that the weapons are designed to penetrate South Korea's missile defense systems to strike stealth aircraft before they can leave the ground.

The move signals that North Korea is thinking about how to strike first in order to win a limited war, an alarming shift for a country that had structured its forces to retaliate in the event of a major invasion.

This week's launch takes another major step to ratchet up pressure on the Trump administration. The regime has carried out a test of its fifth new missile of 2019, a new sea-launched ballistic missile. It is the first missile test since 2017 capable of medium-range flight, the first declared to be capable of carrying nuclear warheads, and the first that has landed in Japan's Exclusive Economic Zone. Given that the US Navy has decades of experience tracking far more capable Soviet submarines, any warheads North Korea puts to sea in a crisis are more of a liability than an asset. However, the test underscores the regime's rapid advancement.

Coming less than a day after North Korea confirmed that it would engage in long-awaited working-level negotiations with US officials this weekend, the launch is a clear signal that the US cannot simply trust that it can have its way if talks resume.

North Korea says it test fired a new type of a submarine-launched ballistic missile (SLBM) on Wednesday, the country's state news agency KCNA reported Thursday morning.

Time for a freeze

The administration's first and only reaction to this year's tests has been to minimize, excuse, or ignore them.

For his part, US President Donald Trump, said that he has "no problem" with the tests even as his diplomats at the UN Security Council criticized them as illegal under international law. He falsely claimed the missiles are "very standard," and repeatedly dismissed the tests as acceptable because they are "short-range."

Trump has yet to comment on the latest North Korean launch but a State Department spokesperson called on Pyongyang "to refrain from provocations, abide by their obligations under UN Security Council Resolutions, and remain engaged in substantive and sustained negotiations to do their part to ensure peace and stability on the Korean Peninsula and achieve denuclearization."

Secretary of State Mike Pompeo previously claimed that the moratorium is only "focused on ... the ones that threaten the United States for sure."

It is a shocking disregard of an ally's security, and a bright green light for Kim to continue testing -- so long as the missiles only threaten allied and American citizens in the region and not the continental US. It is altogether clear that ignoring and minimizing these tests did not sustain negotiations or propel them forward but pushed instead them toward stagnation and collapse.

Rapid advancement in North Korea's missile arsenal over the last year has likely increased the price required for a deal to cap or reduce it, as trust between the parties has further declined, US elections approach and patience among Pyongyang's elite has worn thin.

Since Trump's inauguration, there has been real risk that the US would face an international crisis and the White House would be too mired in scandal to manage it effectively. With the onset of impeachment proceedings, that risk is greater than ever. North Korean negotiators will be acutely aware of the president's tenuous standing if talks do resume.

To the extent that Trump is capable of attending to the North Korea challenge, he will be primarily and perhaps exclusively concerned with deflecting attention from domestic political turmoil rather than reaching a good agreement, tending to Washington's struggling alliances, or adapting to the expanding missile threat.

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Given the President's state of mind and Pompeo's own involvement in the Ukrainian scandal, neither can be trusted to manage a North Korea crisis effectively.

And, if North Korea's demonstrations continue to escalate as the end of the year approaches, there is no telling how a desperate president will react.

The best we can hope for now is that the administration presses pause on North Korea so that his successor has a chance to prevent a new generation of highly advanced missiles from being fully tested and deployed.

A pause could stabilize a delicate situation that stands to deteriorate in the coming months. To do this, the US negotiators should seek a relatively simple initial agreement to limit the expansion of North Korea's nuclear and missile system, including an agreed prohibition on tests of the most dangerous systems.

A missile freeze could provide real security benefits by denying North Korean engineers crucial data from repeated tests of advanced new missile designs and its military the confidence that the systems will work reliably in a crisis. Though modest, this agreement could fairly be sold as a real accomplishment.

Furthermore, the US should endorse and incentivize progress in the stalled inter-Korean negotiations. The 2018 summits between Kim and South Korean President Moon Jae-in produced the only meaningful arms control agreement of the current round of negotiations.

If backed by sufficient South Korean incentives, a revived inter-Korean process is the best hope for conventional arms control that could reduce the risk of war on the peninsula, and the only hope of preserving an opportunity for a future US president to limit North Korea's nuclear forces at this critical juncture in their development.

If the administration had secured an agreed nuclear and missile test freeze at the start of negotiations, or at Singapore, or at Hanoi, talks today would be on much firmer footing and Americans and their allies would be more secure.

After the 2020 election is over, whoever is president will wish we used the last three months to pause Pyongyang's advancements now.