The Congressional Research Service has produced a summary and timeline of recent events pertaining to the United States and North Korea relationship.
In May the Congressional Research Service published a timeline of events relating to the relationship between the United States and North Korea. The document is available here: North Korea: A Chronology of Events from 2016 to 2020.
Here is a portion of the report’s introduction, with footnote references removed:
Since Kim and President Trump’s first summit in Singapore in June 2018, however, little progress has been made on denuclearization, despite two more Kim-Trump meetings (a February 2019 summit in Hanoi and a one-hour June 2019 meeting in Panmunjom). Since the June 2019 meeting, only one round of talks has been held and it did not produce a breakthrough. U.S. officials say their North Korean counterparts have refused to engage in additional negotiations.
The deadlock largely is due to disagreements over the timing and sequencing of concessions that each side should provide.4 In particular, North Korea is seeking significant sanctions relief in return for the steps it claims it already has taken, but U.S. officials have said sanctions will not be eased until denuclearization is complete.
Meanwhile, North Korea appears to be enhancing its military capabilities. In addition to continuing to produce nuclear material, between May 2019 and late March 2020, North Korea conducted multiple short-range ballistic missile (SRBM) tests; such tests violate United Nations Security Council prohibitions. Its motivation was possibly to advance the reliability of its solid fuel and guidance systems and develop capabilities to thwart short-range missile defense systems.
In February 2020 written testimony before the Senate Armed Services Committee, the Commander of U.S. Northern Command said “recent engine testing suggests North Korea may be prepared to flight test an even more capable ICBM design that could enhance Kim’s ability to threaten our homeland during a crisis or conflict.” President Trump has dismissed the significance of these tests. Since the Hanoi summit, North Korea also has largely refused to interact with South Korea, spurning Moon’s efforts.
In a possible signal that the active diplomatic phase of current U.S.-DPRK relations may be coming to an end, Kim in December 2019 announced that, due to the United States’ policies “to completely strangle and stifle the DPRK … there is no ground” for North Korea to continue to maintain its nuclear and missile testing moratorium. Kim criticized the United States’ continuation of sanctions, joint military exercises with South Korea, and shipments of advanced military equipment to South Korea. Kim warned, “the world will witness a new strategic weapon to be possessed by the DPRK in the near future.” The statement noted that this could be adjusted depending on the “U.S. future attitude.”