With big defense cuts looming, this “boom” is for you, Mr. President.

As North Korea’s young dictator promised just a few weeks ago, the Stalinist state carried out its third underground nuclear weapons test late Monday night, following previous big bangs in 2006 and 2009.

Naturally, the latest test is directed at the “reckless hostility of the United States,” according to KCNA, North Korea’s “news” agency; “even stronger” actions might be forthcoming.

But rhetoric aside, while the radioactive details of the latest test leak out, it’s terribly troubling for U.S. security. Some experts think the test may indicate a big breakthrough in the North’s nuclear weapons program.

First, early seismic data indicates this test was not only successful, but the most powerful to date. (The 2009 test was a ground-shaker, but smaller in explosive power, while the 2006 test was more of a “fizzler.”)

North Korea is clearly getting the science of big blasts down pat.

Plus, while unconfirmed, Pyongyang claims that the test used “a miniaturized and lighter nuclear device with greater explosive force than previously (tested).”

This claim of small is big.

If true, this is important to North Korea’s efforts to build nuclear warheads for mating with any of its various ballistic missiles, which are currently only able to carry conventional (explosive) weapons.

Conducting a nuke test is one thing, but “weaponizing” that test platform — engineering it to fit in a missile nose cone and preparing it to withstand the extreme temperatures and pressures of long-distance flight — is another thing altogether.

There’s a good chance Pyongyang used this last test to advance its development of a warhead for its intercontinental ballistic missile (ICBM) program.

Remember back in December when Pyongyang was able to send a small satellite into orbit, using a multi-stage space launch vehicle? The dirty little scientific secret is that if you can launch a satellite payload of a significant weight into orbit, you can also, in theory, launch a nuclear warhead toward a target anywhere on the Earth’s surface — like the good ol’ US of A.

It gets worse.

We still don’t know if the fissile material used in this week’s test was plutonium or uranium. Previous North Korean tests used plutonium, which some observers believe Pyongyang has a limited stock of.

But, if it turns out North Korea used uranium in this test, it would mean Pyongyang has a new pathway for building weapons based on enriching uranium. Meaning? More bombs, and more problems. And even worse is the possibility they would pass along more of their nuclear know-how to Tehran.

Pyongyang’s provocations should remind our leaders, we live in an increasingly dangerous world, and even in trying fiscal times, a strong national defense is not something we can do without.

-Peter Brookes is a Heritage Foundation senior fellow and a former deputy assistant secretary of defense.