Well per your logic, 'luckily' to date Russia hasn't started WWIII as a result of the glider test flights, because as I posted earlier, the Russians can detect launch but not reliably the destination. And, lets face it, the ICBM doesn't need to go anywhere but straight up, then releasing the glider sub-orbital. Presumably the glider can turn, so they can release it in any direction, and presumably it is stealth so Russia won't see where it goes (no doubt the flight path can be carefully chosen as well, if the US can ever work out how to control it lol).
The reason Russia doesn't start WWIII each time a test flight is made is because the US told them of the test, just like in the future they will tell when a strike on a military target proceeds. I don't see it much more of a risk than firing a cruise missile (which can also carry a nuclear payload) albeit other countries will need to be informed as the launch itself is detectable.
Moahunter, before making a snarky comment like this, re-read what I actually posted and pay attention. I specifically mentioned a 'warshot' not a test flight.
The flight trajectory of a warshot targeting a location somewhere in South or Central Asia is very different from the flight profile of a missile test launch. Given the possible trajectories of an inbound ballistic missile targeting something in that region, and the very short response window prior to impact the four nuclear powers in that region would have, do you honestly think that those four countries would believe the US that an incoming strike was conventional? Even if advised of the strike immediately after launch?
If you do believe that other countries would trust the US in such a situation, you either have enormous faith in people, or spectacular naiveté.
As for the employment of cruise missiles vs. ballistic missiles, you seem to not understand some fundamental differences between the delivery system performances and corresponding scenario and range of responses.
Yes, a cruise missile like the Tomahawk can (and used to) have 'special' warheads, specifically nuclear ones. However, a tomahawk follows a nap of the earth flight profile, has a max range of ~1,000 miles, and travels at ~0.9 Mach, which means that a target at max range would be nearly two hours flight time before the cruise missile reached its target. To put it another way, if the USN launched a cruise missile from a vessel at the edge of international waters in the Arabian Sea, off the coast of Iran and Pakistan at a target in Central or South Asia... The cruise missile could potentially hit a target as far away as the south borders of Azerbaijan, Turkmenistan, Uzbekistan, Tajikistan, or possibly the far western border of mainland China, and it would take nearly two hours to get to the target.
A ballistic missile OTOH could be launched from the continental US and still reach those same target areas, but only taking perhaps 15 - 20 minutes to reach the target. Also given the flight profile and a possibly maneuvering warhead, once the inbound warhead is traveling on a ballistic trajectory, it is possible that the warhead could be targeting and reach other areas apart from where the target was claimed to be. And all of this, Russia, China, India and Pakistan would have a matter of only a few minutes to detect, decide, and act/react to.
Again, all the above is if the US were to have developed a Prompt Global Strike system based upon using ICBM's and the US started to take 'warshots' at targets within South and Central Asia.
It is also worth noting that IIRC US defence readiness was routinely raised every time NORAD detected a non-US rocket launch, including launches for the Soviet space programme. This was done in part because many of the rockets the Soviets were using for their space programme were developed from rockets first deployed by the Soviet Strategic Rocket Forces (Soviet nuclear weapons). Given the possibility of a FOBS being launched and triggering a major disruption in US/allied comms and ELINT systems, NORAD typically stood by to advise if a launch was likely a nuke, based upon what seemed to be the rocket flightpath. Until NORAD was confident that a launch was 'mundane' there were usually provisions in place for a rapid nuclear strike, launched before a Soviet FOBS could cripple US C4 systems.