The stock markets rose abruptly Friday on President Trump’s announcement of a ceasefire in our trade war with China. There is no agreement on a trade deal — not even an agreement to agree — but the president suspended application of increased tariffs, at least for a while, as talks go on.

Trump’s unilateral ceasefire comes at a significant moment for China. It has managed to intimidate American companies — most bluntly in the case of the NBA — into self-censorship regarding the Hong Kong freedom demonstrations it may have also done with the president.

According to a CNN report (which is suspect because it is from CNN), in a June telephone call Trump promised Chinese President Xi Jinping that he would remain quiet about the Hong Kong protests while the trade talks went on. Whether or not that report is true, the president has remained silent on those protests — now in their 20th week — and, bizarrely, congratulated Xi on the regime’s 70th anniversary.

Trump’s relationship with Xi is puzzling. Why would an American president congratulate the leader of a regime that has murdered millions and oppresses its more than a billion citizens every day? Has Trump been intimidated or just buffaloed by Xi’s supposed willingness to enter into a trade deal that would end China’s theft of American military and commercial secrets?

Two weeks ago, in the military parade held in Tiananmen Square, the People’s Liberation Army Rocket Force displayed what it claimed were new hypersonic missiles against which the U.S. has no defense. Like those being developed by us, the Russians, and others, the Chinese missile is a “boost-glide” vehicle that could deliver nuclear weapons or destroy large chunks of territory merely by striking at hypersonic speeds.

The reason why we have no defense against such missiles is the natural phenomenon called “plasma stealth.”

We were all taught in grammar school that matter exists in only three forms: solid, liquid, or gas. That’s not quite correct. There’s a fourth form called plasma gas.

Plasma gases can be electronically manipulated in solid containers to do such things as form antennae enabling communications. One inventor I know has already perfected the means of doing so. The applications for such antennae include stealthy aircraft and missiles that could have highly effective communications without external antennae that increase their detectability by radars.

Plasma gas occurs in nature, albeit far less than the other forms of matter. It is ionized gas — i.e., a gas, such as those found in the atmosphere — in which the atoms of the gas lose an electron and thereby become more electromagnetically active and unstable. That brings us to plasma stealth.

In 1957, American radars were trying to track Russia’s original Sputnik satellite in low-earth orbit, effectively within the outer limit of the atmosphere called the ionosphere. Sputnik was traveling at orbital speed, about 17,500 miles per hour or Mach 23.

The satellite was traveling in a naturally created ionic plasma cloud that in turn created two different radar shadows that effectively canceled each other out. Thus, Sputnik was at times invisible to radars because it was shrouded in a plasma cloud. That means plasma stealth isn’t just theoretical: it can be accomplished.

Hypersonic weapons such as the Chinese DF-100 are supposed to be able to be boosted to speeds of Mach 5 and higher. They would be trackable by conventional radar in their ascent stage to their maximum altitude, where they would tip over and then reenter the atmosphere at speeds of Mach 10 or higher.

If the missiles were equipped to electrically charge their skins, they would create a cloud of plasma shrouding the missile’s body. Even if we had interceptor missiles that could catch and kill them, we couldn’t target the incoming missiles because they would be invisible to radar.

We don’t know if the Chinese (and Russian) claims that they have perfected hypersonic missiles that cannot be detected by radar are true. (Russian President Putin announced in March 2018 that Russia already has such missiles.)

The Chinese “missiles” displayed in their October parade weren’t missiles themselves, just big missile casings hauled on what the Chinese claim are launch vehicle trucks. Again, we don’t know if their claims of success in hypersonic missile development are true.

The Chinese and Russian claims of success in developing hypersonic boost-glide missiles pose a question of national security that disrupts our theory of deterrence through “MAD” — mutually assured destruction. They are clearly first-strike weapons that cannot be defended against by our current defense systems.

The risk they pose can be answered in several ways. First, by our own development of such weapons, which is proceeding at our usual pace, meaning very slowly. It takes two decades for us to field weapon systems such as fighter or bomber aircraft. There is no reason for the development of hypersonic weapons to succeed faster.

The other way to answer the threat such missiles pose is for us to develop systems to detect and kill them in their boost stage, before they tip over into the atmosphere and are plasma-shrouded. That would necessitate making the decision to develop and deploy weapons — such as a modern version of the Reagan-era “Brilliant Pebbles” system that was never built — which is a decision that neither we nor our adversaries have been willing to make.

The idea that space is a region where weapons do not exist is a fallacy. China successfully tested a ground-launched satellite killer a dozen years ago. Russia has reportedly — and successfully — tested its mobile satellite killer, the PL-19 Nudol, at least seven times.

Both the Russians and the Chinese are developing hunter-killer satellites that could orbit for months or years awaiting signals to destroy our satellites, crippling our abilities to securely gather intelligence, communicate, navigate, and detect missile launches by our enemies. (Our Space-Based Infrared System — “SBIRS” — can probably detect any launch of even small, short-range missiles and give almost instant warning to our defense systems.)

Hypersonic “boost-glide” missiles and satellite killers are designed to make MAD’s deterrence obsolete and to tip the balance of power decisively in the direction of those who can first deploy them. They are weapons of intimidation that will affect us and our allies in a way that must be answered very soon.

By their impeachment proceedings against him, the Democrats have diverted President Trump’s attention from almost anything else. Neither we nor our allies can allow him to ignore the effort to make MAD obsolete. He has some tough decisions to make on the matter of the further weaponization of space. Those decisions must be made quickly, whatever else may be diverting him from his duties.