The world is getting smaller all the time and it seems that the US Marine Corps has finally noticed. The SUSTAIN or Small Unit Transport and Insertion program is designed to allow them to get a squad of marines, traditionally the first US armed force deployed into emergency situations, in two hours. They intend to do this by taking a very old and very effective short cut.
SUSTAIN proposes that a suborbital transport, a vehicle that would 'pop' up above the atmosphere and then back down over the target point could reach far higher travel speeds than before and give the Marines a vital tactical advantage. This sort of trajectory is, ironically, the same one employed by the Mercury Project's early flights, sending the first US astronauts in looping arcs out of the atmosphere and back again. However, SUSTAIN calls for something a little more advanced than Mercury's boilerplate technology: a troop deployment vehicle designed specifically for the job. As a result, the project is as concerned with developing the technology over the next three decades as it is with the final result.
The technology needed for SUSTAIN is a lot closer than you might think too with hypersonic propulsion systems in development in numerous countries, including the Skylon program developed by British rocket scientist Alan Bond. With this in mind, and Congress backing them, the Marines expect to develop a prototype inside 15 years which is initially planned to be a two stage aircraft, possibly similar to one of the original designs for the space shuttle. Of course then it's just a matter of time before a SUSTAIN pilot modifies the technology for his own ends and opens some sort of international rescue organisation with his sons...