TWO US space forces already exist- that's where plenty of that $21 Trillion has been secretly siphoned off to. A space force isn't a stupid idea at all not only is it essential to the security of our solar system and planet but it's also essentially to establish ourselves in the galactic community.
The premier program is the USN Solar Warden program- this fleet consists of I believe 8 battle groups with interstellar capabilities. The first ships were launched in the 1980's and this force acts as the police force for our solar system keeping track of the MANY various ETs that visit our Sol System- Our Sol System's location has situated us well as a trading hub for this part of our galaxy.
The other space program already in existence is the USAF/DIA's program that isn't interstellar but instead focuses on Earth's orbital space. This force uses the triangular zero gravity ships seen/photographed many times and also has two large orbital space stations that are at least 50 years more advanced than the ISS (merely there for show). I have seen these space stations many times - they are easily visible from the east coast of the US on a clear night and move with the stars but aren't stars at all.
So not only can we afford a Space Force- we already have two and they are essential to our security and the expansion of our species into the heavens to continue our evolution as a species- you'll see as the announcement of the formation of this 'Space Force' was in reality a soft disclosure first step in disclosing the existence of our Space Force.
You may want to do some research on the late William Tompkins- he designed some of the USN's Solar Warden ships- also have a listen to Corey Goode who served in Solar Warden and check out Cosmic Disclosure on Gaia TV. Dr Michael Salla's work may also interest you if you choose to research this topic.
I wonder if anyone ever said to JFK that we couldn't afford the Apollo program? I say humanity can't afford to NOT have a viable Space Force. Don't let your politics interfere with the progression of our species. ETs who have visited us for decades now have advised select humans that we can either have a war based economy or a space based economy- I say we choose space/exploration over war.