The news last week from the Pentagon’s supersecret Defense Advanced Research Projects Agency that it had successfully tested a hypersonic missile capable of speeds up to 3,082 mph caused quite a stir in military circles, and no wonder. Imagine being able to aim at and hit any target on the planet within an hour; or soldiers in Afghanistan calling in a pinpoint airstrike with missiles fired from Omaha.

Taken together with the successful test by the Office of Naval Research over Halloween of its hypersonic electromagnetic railgun—which, once it goes into action, can knock out approaching missiles as far away as 100 miles—and we may be entering an era as revolutionary as when gunpowder replaced the crossbow.

Unfortunately, now that Congress’ supercommittee has failed to reach some kind of budget deal, we may be doomed to crossbows for good.

The resulting sequestration of funds could strip away as much as $1 trillion from defense spending over the next decade—and put future weapons systems like hypersonic in permanent eclipse.

The House Armed Services Committee’s Democrats and Republicans have issued a chilling report on what happens if sequestration sets in.

"Unfortunately, now that Congress’ supercommittee has failed to reach some kind of budget deal, we may be doomed to crossbows for good."- Arthur HermanWe’ll be losing 60 ships from the Navy, including two carrier battle groups, and we’ll have 200,000 fewer troops than in 2010. Production of the Army’s Apache attack helicopter and Kiowa reconnaissance helicopter will have to shut down. No vertical take-off F-35 fighter for the Marines—and no next generation bomber for the Air Force. On top of losing ships, the Navy will also see fewer and fewer replacements, as lack of cash slows production schedules.

Is there wasteful spending at the Pentagon? Sure. Are certain weapons programs like the F-35 running way over budget? Of course. Does the military service’s very expensive health-care and retirement systems (the fastest-rising costs in the entire Pentagon budget) need some revamping and new thinking? Absolutely.

But the sequestration budget cuts will run up the white flag for friends and foes alike—and require major mission shrinkage in places like the Pacific, Africa and the Middle East. And they’ll mean losing the future while the Pentagon scrambles to save what it can of the present.

Which brings us to hypersonic. Programs involving first-time technologies have historically been extremely expensive to develop and engineer, and almost as costly to test. Like ballistic missiles in the 1950s and the Strategic Defense Initiative in the ’90s, expect serial failures on the launching pad until the technology is understood, let alone perfected. DARPA’s two earlier test hypersonic vehicles both crashed and burned—though not before the last reached Mach 20, an incredible 20 times the speed of sound.

But even if the will to persevere is there, the funding may not be. Future Congresses laboring under sequestration rules, and facing headlines proclaiming still more costly delays in a “flawed” hypersonic program, will be tempted to cancel the whole thing.

Congress has already cut funding for a free-electron-laser program. And despite successful tests, money for railgun development has been terminated, as well.

If hypersonic is next, the United States may be unable for the first time since World War II to exploit the next major military technology revolution—and so fall permanently behind those who are willing to try, including (inevitably) the Chinese.

The good news is that the Budget Control Act still allows Congress and the president to propose alternative cuts even after sequestration beings. This law was never meant to grind the government to fiscal standstill—or hollow out our military.

But those hard choices will now be postponed until the 2012 election—when American voters have to decide whether they want a permanently weakened defense structure or are willing to use the savings from our withdrawal from Iraq and Afghanistan to modernize our military for the threats to come, from a nuclear Iran to a hegemony-minded China.

Meanwhile, the future of America’s military superiority hangs in the balance—and by a budgetary thread.

Arthur Herman is a visiting scholar at AEI