The bombs that dropped on Hiroshima and Nagasaki were fission bombs. When isotopes of uranium or plutonium break into smaller particles, energy is released, and the Hiroshima and Nagasaki bombs channeled that energy into an explosion. In a civil nuclear power generator, by contrast, the release of fission energy is controlled, and used to power the electrical grid.

The energy from the sun comes from fusion. Under the weight of the sun’s gravity, and channeled by vast heat, isotopes of hydrogen fuse with each other to create a new, heavier, element called helium. Helium, indeed, was first detected in the sun, which is how it got its name: helios is the Greek word for sun.

We humans have been harnessing the power of nuclear fusion since 1952, when the United States exploded Ivy Mike on an atoll in the Marshall Islands. Technically, Ivy Mike was a thermonuclear device, but because they fuse isotopes of hydrogen into helium, such devices are generally called hydrogen bombs.

Unfortunately, however, the civil production of electricity from fusion has yet to be achieved, which is indeed unfortunate because fusion produces neither CO₂ nor radioactivity. A civil fusion power generator would produce baseload energy that was clean, that would avoid global warming, and that—in contrast to many renewables—would not vary output depending on the sun and wind.

But creating a civil fusion power generator would require such high temperatures and compressive forces that, to date, progress has been slow. Indeed, the cliché has long been that every year since 1952 we have been told that the production of civil fusion energy will be achieved in thirty years.

But perhaps that thirty year target might finally be achievable, because the Lawrence Livermore National Laboratory in California has announced that, on using lasers to pump 2.1 megajoules of energy into a fusion reactor, 2.5 megajoules of energy was released. Actually, that calculation was a bit of a cheat, because it did not include the enormous amount of power the lasers had dissipated before they injected their final 2.1 megajoules into the reactor, but nonetheless this result—should it be reproduced—represents a significant milestone in our march to generating civil fusion energy here on planet earth.

But why is the government performing this research? The potential profits from civil fusion are truly vast, so the private incentive to pay for the R&D is obvious. Indeed, the clumsily-named ‘Forum FUSION Germany’, which is a German government/​private forum for the discussion of fusion, held its second meeting in Garching, Germany, last week, where it was announced that investors, largely from the U.S., had already committed at least $4 billion to civilian fusion research. Some of the largest companies include Commonwealth Fusion from Cambridge, MA ($2 billion) and TAE Technologies from Foothill Ranch, CA ($1.2 billion), but there seem to be about 30 fusion start-ups globally, ranging down to Phoenix from Madison, WI ($29 million).

None of which is surprising, because most of our important technologies have come from the private sector: Faraday, Edison and Tesla—all in the private sector—gave us the electromagnetic generation of electricity; the Wright brothers invented the airplane; Robert “Moonie” Goddard created the first space rockets; the list goes on.

But government funding can crowd out private funding, and the federal government can monopolize a technology. NASA was a space monopolist for decades, and it behaved as such, sustaining costly facilities in states such as Mississippi and Alabama not to promote space exploration but to buy congressional support by creating local jobs. Unsurprisingly, therefore, it has fallen to the private sector to invigorate the exploitation of space: witness SpaceX, Blue Origin and Virgin Galactic.

The worry today must be that the Lawrence Livermore National Laboratory is already eyeing up the most propitious states and the most propitious congressional districts in which to next fuse hydrogen into helium, not because the chemical elements care about their geographical location but because a government program must, by definition, work to government and not market imperatives.

Certainly, the Lawrence Livermore National Laboratory will proffer all sorts of reasons why the American taxpayer should continue to support its fusion research, but only one stands up to scrutiny, because any claims that the Laboratory would do a better job than the private sector in preventing climate change or in providing cheap energy can be rebutted simply by juxtaposing NASA’s facilities in Mississippi and Alabama against SpaceX, Blue Origin and Virgin Galactic. If NASA wasted your money (and it did) so would the Lawrence Livermore.

The only good reason for the federal government to fund fusion research is defense: we live in a dangerous and unpredictable world, and the pressing, perennial, overarching geopolitical goal must always be to ensure that the democracies are better armed than the alternatives, whether they be in Russia, China or Iran. Indeed, the New York Times understands that that is why the federal government is funding this work: “By performing these nuclear reactions in a lab at a less destructive scale, scientists aim to replace the data they used to gather from underground nuclear bomb detonations, which the United States stopped in 1992.”

Inasmuch as the Lawrence Livermore’s fusion research is defense-orientated, so should it be supported. And generously. But if the Laboratory is trying to butt into the commercial market, it should be told to butt right out again.