The outer space treaty is very specific.
the exploration and use of outer space shall be carried out for the benefit and in the interests of all countries and shall be the province of all mankind;
outer space shall be free for exploration and use by all States;
outer space is not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means;
States shall not place nuclear weapons or other weapons of mass destruction in orbit or on celestial bodies or station them in outer space in any other manner;
the Moon and other celestial bodies shall be used exclusively for peaceful purposes;
astronauts shall be regarded as the envoys of mankind;
States shall be responsible for national space activities whether carried out by governmental or non-governmental activities;
States shall be liable for damage caused by their space objects; and
States shall avoid harmful contamination of space and celestial bodies.
THis treaty was ratified by the US on Jan21, 2005. Sure, go ahead and break this treaty for a non-essential project. Thus, the USA cannot be trusted in it's promises, and shall not receive reciprocal treatement by other nations. For instance, on the Convention on the High Seas treaty, Article 8 states
1. Warships on the high seas have complete immunity from the jurisdiction of any State other than the flag
State.
In other words, if the USA breaks treaties, then anyone is allowed to sink a US registered ship and get away with it. Imagine some Cuban gunboat sinking a cruise liner fresh out of Miami...
Or the second a nuclear warhead lifts off the ground, Russia, China, and other would quickly install battle satellites in space, and that means nuclear weapons pointed at the USA, and all just orbiting just a few hundred miles up.
Or.. since the US breaks treaties, then US soldiers are not subject to the Geneva convention and can be tortured or killed by anyone who captures them.