35 years ago a young boy, I would say YES!!!!!! That's due to not truly understanding the harsh realities of space and life in general.
After spending decades learning about space exploration, military doctrine and history of human nature period, the three aspects do not mesh very well.
Space is 100% all the time trying to kill you. The human body is unprotected in outer space from the vacuum, radiation, extreme cold and hot temperatures and dust particles. The spacecraft we utilize shelters the human body , but is also susceptible to the same elements once the structure integrity is breached placing the human in mortal danger. Yes, humans who go off to space accepts those risks.
This is about the extreme hostile environment in outer space, the surface of the Moon and Mars.
Military doctrine is simple. Kill the enemy. Create superiority in all phases of combat. Control the situation. Make the enemy crushed beneath your feet. That is required to win a war. No question.
Finally, the history of human nature gives way too much for discussion. It can be kept to a simple way of explanation. Power. From power, individuals throughout history took opportunity, resources and initiative to build great things or start violent things. Mankind is inherently good as a whole, but laced with some bad apples.
Using those 3 ideas, the real reason a military branch that would be given the charter for space supremacy would result in one conclusion. No one wins.
Space combat would not be like Star Wars or Battlestar Galactica. You don't need gigantic spacecraft with massive directed energy weapons for reminiscent battles on open water with sailing ships in broadside cannon fire. Natural resources in the solar system will be the ammunition of the future.
A colony on Mars or the Moon would be destroyed by the "raining down" of large rocks from orbit. Spacecraft would tow and release the rocks for best trajectory below. The damage would be so severe that all humans would die from the hostile environments. Emergency shelters would eventually run out of sustainable power and survivors would die from lack of oxygen and heat. long before any rescue attempts could be made.
Small powerful unmanned spacecraft would be used in suicidal runs on space stations, manned spacecraft and colonies. Result: loss of all life.
This is using Goddard rocket principles. Putting fuel in the bottom of a rocket and lighting the match. Which is still expensive to launch and to waste in a future space conflict.
Plus, there is that vast debris field in orbit that places risk on all space flight activity. Once, there is active armed aggression, then more debris will result tragically risking the safety of humans in space.
Missiles, bombs and bullets don't belong in an environment where once your protective structure is compromised, you are at risk of death without rescue.
Now, should there be a time in the future where a military branch dedicated to the safety and defense of space be needed? Possibly.
1) When a belligerent nation actively begins space warfare. No. That nation can be stopped on Earth. Cut the legs from the ground and that space program fall from the sky.
2) When corporations become hostile in space. No. They can be stopped on Earth as well.
All human space activity will be completely dependent on Earth support. we don't have the power generation to maintain self sustaining space stations and colonies right now. It will be long into the future before that bridge is crossed. Private companies will be hard at work trying to make that an eventually.
What would be the only true reason for a military branch in space? This one is still in the realm of science fiction. It would require for the US government to openly announce and provide empiric evidence of alien species that are hostile to humans. Something like that would require the cooperation of all nations working together.
Until that scenario becomes a reality, the money to spend on a proposed US Space Force (which right now would be a token force of a few personnel and some offices in the Pentagon of around several hundred thousands of dollars) in the tens of billions each year and escalating to fund that level of force projection would be better used on realistic problems. Public education, health coverage, homeless, illiteracy, hunger, and other issues presently in our nation.
That's my two cents.
