Militaries should be organized from the bottom up, with elected tacticians and temporary commanders under the threat of instant recall, and should exist in a state of organizational servitude to the security of the civilian population against external violence. If used for attack, it should focus on a campaign of terror against domestic slavers, human-traffickers, and union-busting employers, to the extent that this is allowed by the civilian population; while providing material and moral support to anti-authoritarian struggles in other countries where so authorized. I would be enthusiastic to serve a tour in that infantry, personally.
Under the current regime, the US military is organized as a hierarchy in service of the corporate backers of the executive and legislative branches. It currently serves the interests of a small splinter of civil society, much of it consisting of people whose major contribution to society is supplying goods and services to the military itself. It is a recursively-corrupted meta-organization whose every nook and cranny has a secret big or small: much shall be legally hidden from you as a soldier, while other laws are broken by indispensable technicians and the sergeants and lieutenants who are compelled to keep their secrets. Integrity is rare, and rarely goes unpunished. You will sign away more rights than you can reasonably be expected to understand, and will become an easy mark for exploitation with your freshly deindividualized mind and your underpaid, potentially exhausting work. Even in the Guard, you're more likely to see combat than your recruiter would ever admit, and if you do see combat, you're likely to contract an injury or illness that will be inadequately treated to the extent that you depend on the military; PTSD, TBI and MST are insanely common in the US military, as is suicidality.
You will be taught to venerate power and become fundamentally obedient, but you will be punished if you receive an illegal order (whether or not you carry it out). Your capacity to develop independent political opinions will be weakened, as by any association, but especially so by an explicitly authoritarian organization. The sphere of your normal life will be partially displaced from those of your countrymen, but mostly in the most grueling and soul-crushing ways, leading many of your colleagues to resent your fellow Americans and the rule of law, and tempting you to join them. You will learn to prioritize the government's needs over your own, endangering your capacity to participate in a democratic society. You will lose the respect of your freedom-loving countrymen, who will fear and in some cases despise you, especially if you are stationed amidst a culture clash in a hostile city. You will expose yourself as the first non-VIP, non-Super-Bowl type target on any terrorist "pro/con" list, while being treated by your own military organization as an enthusiastic would-be criminal who is barely kept in line by micromanaging your life choices. You will be a target on planes and in foreign countries, potentially seeing your freedom of movement restricted. What few benefits you are considered to have earned in society, you will have to fight and scrap for, and you may miss out on significant chunks of them because you were distracted during the short window of time you had to sign up for them. What few freedoms you retain will often be kept more or less secret from you until it is too late to use them, etc.
On that note, remember to read every word that you are asked to sign, and if you do sign a contract, remember that you can walk away from it freely, with absolutely no consequences, through the first 72 hours of Basic Military Training ("boot camp") only. Familiarize yourself with relevant passages of the UCMJ (Uniform Code of Military Justice), especially trainee rights and responsibilities, whistleblower rights, protest/dissent/speech rights (and lack thereof), etc. You will meet superiors who abuse their power, give you illegal orders and/or attempt to control your behavior in ways that they do not have the authority to do. For example, remember that no political or cultural organization is illegal for a soldier to be a member of except for white-supremacist groups, but it is also illegal to criticize the president during wartime or refuse involvement in any kind of war action (except for illegal orders which, again, you will probably be punished for receiving one way or the other).
