It's time for the United States to hold Iran accountable.

North Korea's fourth nuclear test could have been a crucial step toward Pyongyang developing thermonuclear capability — and a breakthrough for a second country with potential nuclear ambitions, as well.

Iran has established ties to the North Korean nuclear-weapons program. As The Daily Beast notes, Iranian officials, including Iranian nuclear program head Mohsen Fakhrizadeh, were present during North Korea's three previous nuclear tests — in 2006, 2009, and 2013.

Testing data is a potential bonanza for a nuclear-weapons program. It could include information about the design and yield of the device detonated — or about the size and configuration of the bomb's uranium hemisphere or plutonium core. Testing data could indicate the weight and shape of the nuclear device, its triggering mechanisms, or the warhead's material composition.

As Simon Henderson of the Washington Institute for Near East Policy has written, there is also some design and technological overlap between Iranian and North Korean-produced ballistic missiles, suggesting the two countries have shared information about nuclear delivery platforms as well.

Last July, Iran reached a deal with a US-led group of world powers in which Tehran agreed to temporary and non-binding limitations on its nuclear program.

Those came in exchange for the eventual lifting of most US and nearly all United Nations and European sanctions on the country, in addition to the removal of embargoes on the country's conventional arms transfers and ballistic-missile development.

It wouldn't necessarily be a violation of the nuclear deal for Iran to access information from a North Korean nuclear test. Thomas Moore, a former non-proliferation expert for the Senate Foreign Relations Committee, told Business Insider that he doesn't think that accessing this information would necessarily be a violation of the Nuclear Non-Proliferation Treaty (NPT), either.

Like the NPT, the Iran nuclear deal is deliberately vague on exactly what constitutes a violation. But possession of test data isn't specifically proscribed under a provision in the Iran agreement that addresses prohibited activities related to nuclear-weapons design.

Under the deal, potential violations will be brought before an eight-member "joint commission" that includes Iran. The commission can then vote on whether an alleged violation is serious enough to then refer ot the United Nations Security Council.

Enforcement of what is inevitably a non-binding agreement is dependent on the political will of the joint commission's members. And the text itself is elastic in ways that could permit Iran to access information relevant to a push towards a nuclear-weapons capability.

Read the full story from Business Insider.