McMaster thinks North Korea can't be stopped from attacking the US or allies

President Donald Trump's national security adviser made a startling statement to ABC's George Stephanopoulos on "This Week" on Sunday.

When asked whether or not the US could tolerate a fully nuclear-capable North Korea, Lt. Gen. H.R. McMaster questioned how the military has dealt with nuclear nations for decades.

"The classical deterrence theory, how does that apply to a regime like the regime in North Korea?" asked McMaster.

McMaster characterized North Korea as engaging in "unspeakable brutality against its own people," as posing "a continuous threat to the its neighbors," and now the US with nuclear weapons, as well as imprisoning and murdering "anyone who seems to oppose that regime, including members of his own family."

Trump's top national security advisor fundamentally believing that North Korea cannot be deterred has massive policy implications. Essentially, if North Korea cannot be backed down by the US's superior nuclear might, then it makes sense to attack before it develops full nuclear capability.

But McMaster's characterization of North Korea as a regime beyond the pale of rationality has some issues of its own. To varying degrees, both the Soviet Union and China engaged in similar brutality, threats, and murder and oppression of dissidents.

In 1957, during the US and Soviet Union's heated arms race, Chinese leader Mao Zedong said "I'm not afraid of nuclear war. There are 2.7 billion people in the world; it doesn't matter if some are killed. China has a population of 600 million; even if half of them are killed, there are still 300 million people left. I'm not afraid of anyone."

But nuclear war never broke out. Though the US sought to contain the spread of communism during the Cold War, it never attacked China, even as it built its own nuclear arsenal.

Experts contacted by Business Insider have said in the past that Kim Jong-un is indeed a rational actor who can be expected to observe established rules of deterrence.

The consensus among North Korea watchers is that Kim seeks nuclear weapons for regime security, and while his newfound nuclear prowess could strike a US city, the US's response would leave nothing left of North Korea.