North Korea's nuclear and ballistic ambitions have existed for decades: The country conducted its first significant missile test launches in the 1980s, and conducted its first nuclear test in 2006. Now, thanks to a recent surge of development, the intertwined endeavors have both advanced to the point that experts have warned about for years. The worst-case North Korea hypotheticals, in other words, have suddenly become all too real.

A report from the US government's Defense Intelligence Agency indicates that North Korea finally has the technological capability to reliably build warheads that are small and light enough to be mounted on missiles. This "miniaturization" capability has long eluded the country's weapons development program. But now that North Korea has achieved it, the list of hurdles keeping the country from directly threatening the continental US (or virtually any part of the world) with an intercontinental ballistic missile has dwindled significantly.

The intelligence community consensus that North Korea can miniaturize nuclear warheads, first reported by The Washington Post, adds to an already strained and unpredictable geopolitical climate. Recurrent North Korean missile launch tests have underscored the country's determination to become a full-fledged nuclear power, while recent UN sanctions against the country have stoked tensions even more. The weapons advances were always a question of when, not if, but they are coming sooner than many expected.

"There were some officials both inside and outside of government who already believed that North Korea had the capability to mate a warhead to a missile, but it certainly wasn’t the consensus view," says James McKeon, a policy analyst at the Center for Arms Control and Non-Proliferation. "On North Korea’s current trajectory, though, there was no doubt that they were going to get there eventually unless something changed, unless there was a form of diplomatic negotiation or something that stopped them from getting there."

Compounding the nuclear issue? North Korea pulled off its first successful intercontinental ballistic missile launch in early July, testing a Hwasong-14 missile that traveled 580 miles and reached an altitude of 1,741 miles during a 37-minute flight. Based on that test, analysts concluded that the Hwasong-14 might be able to travel more than 4,000 miles, putting Alaska in its range, along with countries like Japan. This radius even potentially puts Moscow at risk. Another successful ICBM test followed at the end of last month; North Korea issued commemorative stamps to celebrate.

Taken separately, North Korea's possession of a miniaturized nuke and an ICBM would be plenty concerning, not just for the US but for the entire world. Combined, they present a significantly more serious threat. Playing to these fears, North Korean state-run media claimed on Tuesday that the country is considering a missile strike on Guam. At more than 2,000 miles away from North Korea, the island nation would be significantly more difficult to target than US allies like South Korea or Japan—a possible indication that the threat is an escalation of saber rattling rather than intent.

Researchers who analyze the North Korean missile program have long cited lack of demonstrated miniaturization as evidence that comprehensive nuclear missile capabilities were still at least a few years away for the country. And experts note that the US intelligence community's latest assessment doesn't mean a North Korean ICBM could reach around the world today. There are still real questions, they say, about the reentry technology on North Korean missiles—can they withstand the heat and force of reentering the Earth's atmosphere?—and the accuracy of their targeting systems. Developing reliable guidance technology is challenging and impacts every other subsystem.