Could there be any legal repercussions for wearing this in the US (I
am not affiliated with the military), without any other military
clothing (eg. with civilian pants)? Is it necessary to remove the
nametag and other insignia?
Yes, according to the law wearing a US military uniform is prohibited unless you have explicit permission (usually by being in the military):
Except as otherwise provided by law, no person except a member of the
Army, Navy, Air Force, or Marine Corps, as the case may be, may wear—
(1) the uniform, or a distinctive part of the uniform, of the Army,
Navy, Air Force, or Marine Corps; or
(2) a uniform any part of which
is similar to a distinctive part of the uniform of the Army, Navy, Air
Force, or Marine Corps.
10 U.S. Code § 771. Unauthorized wearing prohibited
The penalty is up to six months imprisonment:
Whoever, in any place within the jurisdiction of the United States or
in the Canal Zone, without authority, wears the uniform or a
distinctive part thereof or anything similar to a distinctive part of
the uniform of any of the armed forces of the United States, Public
Health Service or any auxiliary of such, shall be fined under this
title or imprisoned not more than six months, or both.
18 U.S. Code § 702. Uniform of armed forces and Public Health Service
Exceptions to this rule are listed in § 772. When wearing by persons not on active duty authorized. These are mostly the exceptions you would except (retired military personnel, actors in a performance, civilians working with the military or attending a military school...).
In addition to that, there is legislation that specifically outlaws claiming to have earned medals or awards - for example, the Stolen Valor Act of 2013, which makes it a crime to fraudulently claim having received an award. So adding a medal to your uniform could cause additional problems, at least if the prosecution thinks you did it to defraud others by claiming to have received the medal rightfully.
Some things that may save you:
- In practice, it is, as usual, at the discretion of the district attorney whether a violation will actually be prosecuted.
- Courts have ruled that the exception for actors must be interpreted generously, so for example Halloween costumes may be covered under that exception.
- The law specifially forbids wearing "the uniform, or a distinctive part of the uniform". So as long as you only wear a part of the uniform (e.g. only the jacket), you are safe, unless the part is considered to be "distinctive". There are specific regulations on that (no source handy right now), but basically only the decorative or rank elements are "distinctive" (badges, tabs, buttons, medals, ribbons, headgear etc.). The purely "functional" items (such as jackets, backpacks, boots etc.) are probably safe (but no guarantees from me, obviously!).
That said, there have been successful prosecutions for violating §771, especially if the court judged it was done specifically to denigrate the US armed forces.
Finally, note that there are additional regulations around uniforms in the Uniform Code of Military Justice (which applies to members of the armed forces), so as an active soldier, you may face additional consequences.