As they bicker, Chinese companies aren’t waiting ... and U.S. producers fear that they’re being shut out of a quickly developing new technology by their own government.

Now, as 5G moves quickly from a sales pitch to a business reality, a significant battle is erupting between wireless carriers, which want the government to free up the Pentagon’s share of the mid-band airwaves for commercial use, and Pentagon generals, who warn of national-security risks if they lose control.

As they bicker, Chinese companies aren’t waiting: Huawei and others are moving quickly to build and sell equipment that exploits exactly those frequencies. As other nations stock up on infrastructure built by Huawei and other Chinese firms, gear from China is becoming the standard in much of the world — and U.S. producers fear that they’re being shut out of a quickly developing new technology by their own government. The Pentagon, too, is likely to face security concerns in its overseas operations as its mid-band channels get crowded by Chinese-built devices.

Though it hasn’t cracked the front pages yet, the battle over the mid-band airwaves has created strange political dynamics of its own, with big telecom companies trying to budge the Pentagon without triggering an open lobbying war, and Newt Gingrich and Trump campaign manager Brad Parscale joining the battle on behalf of yet another would-be player in the industry. In the process, it’s focusing attention on a big mystery: What is the Pentagon even doing with its valuable slice of the wireless spectrum?

And, with China racing to exploit its lead, the lack of mid-band open to American companies is raising a bigger worry for U.S. competitiveness: Even if the Pentagon finds a way to free up some of the territory, China’s growing head start may mean it’s already too late.

The airwaves are one of the least understood resources in America — invisible and all around us, they power everything from military radar to home Wi-Fi to old-fashioned AM radio. They’re also a top-level tug-of-war in Washington. Theoretically owned by the public, they’re regulated by two separate agencies, neither answerable to the other.

Nearly a century ago, when the invention of radio made it clear that that the airwaves — technically, the electromagnetic spectrum — would be as useful to commerce as to science, Congress created the Federal Communications Commission. The new independent agency would grant licenses to commercial entities like radio operators, TV broadcasters and telecommunications companies. But separately, it also granted the Commerce Department authority to reserve and manage some of the spectrum for government purposes. Today, the FCC auctions parts of the spectrum to private companies, but has no authority over the sizable chunks that Commerce has allocated to agencies such as the Department of Defense.

When the system was set up, that wasn’t a big deal; the airwaves were big enough for everyone. But as radio and TV have been joined by cell carriers and other uses, the commercial airwaves have become more crowded and more valuable, with companies bidding for long-term leases to use certain frequencies. The prices have become dizzying: A 2015 auction of several slices of federally controlled airwaves raised nearly $45 billion.

Not all spectrum is equally useful. At the low-frequency end, signals can travel great distances and penetrate objects, but carry very little information. At the high end, so-called millimeter-wave bands can carry huge quantities of data, but don’t travel far and can be blocked by leaves or even thin walls.

For the emerging 5G network, the “mid-band” occupies a sweet spot between data and distance. Mid-band signals can carry much more data than current cellphone networks without requiring overly dense networks of relay antennas. Mid-band signals look highly desirable to firms trying to connect everything from self-driving cars and surveillance cameras to drones making pinpoint deliveries and even doctors performing remote surgery.

They’re also desirable to the military. The Department of Defense has long laid claim to large pieces of the electromagnetic spectrum for the ever-growing role of electronics in military operations, and by the late 1960s it was clear that the Pentagon wanted, and would hold onto, much of the mid-band.

Battle of the mid-bands