A May 22 Washington Post story reported that in mid-May top national security officials discussed resumption of full-scale US nuclear explosive testing. The next day, the Abolition 2000 Global Network to Eliminate Nuclear Weapons was holding, virtually, its annual meeting.

The meeting released a statement, co-authored by Burroughs (see previously circulated press release). It begins:
“Resumption of nuclear explosive testing is absolutely unacceptable. Even discussing nuclear testing again is dangerously destabilizing.” The statement also observes: “This episode comes in the context of ongoing upgrading of nuclear forces by the world’s nuclear-armed states. It is supported by extensive laboratory research and experimentation which in part serves as a substitute for functions once served by nuclear explosive testing.”
Since the Washington Post story, there have been no further signals of returning to full-scale nuclear explosive testing. But at a minimum the White House discussion demonstrates that the option remains alive. Senator Ed Markey and numerous co-sponsors including Senator Chuck Schumer have introduced legislation that would prohibit the expenditure of funds on conducting nuclear test explosions with any yield. A parallel bill (H.R.7140) has been introduced in the House.

Adoption of such legislation would be very much to the good.
Even better, when politically possible, would be Senate approval of ratification of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) followed by presidential ratification. In a vote held in 1999, the Senate failed to approve ratification, but consideration of the CTBT remains on the docket of the Senate Foreign Relations Committee.
A promise by the NPT nuclear-weapon states (US, UK, France, Russia, China) to complete negotiations on the CTBT by 1996, which was done, was an essential part of the bargain that enabled indefinite extension of the NPT in 1995. Bringing the CTBT into legal force was a commitment adopted at the 2000 NPT Review Conference. The CTBT is the only arms control measure referred to in the NPT, and its enactment has always been viewed as key to achievement of the NPT objective of cessation of the nuclear arms race at an early date. 
The UK, France, and Russia have ratified the CTBT, and the US and China have signed it. The last test by an NPT nuclear-weapon state, France, was in 1996, accompanied by worldwide protests. India and Pakistan have not tested since 1999. Security Council Resolution 2310 of 2016 calls upon all states not to conduct nuclear test explosions. There is clearly a global expectation – at least a political norm – that the era of nuclear explosive testing is over. Accordingly, any state that does test, as the DPRK has, is effectively an outlaw. Moreover, under international law the United States and China are obligated by their 1996 signatures of the CTBT not to act contrary to the object and purpose of the treaty, which testing unquestionably would do.
For all these reasons and those spelled out in the Abolition 2000 statement, the option of resumption of nuclear explosive testing should be taken completely off the table.