The ACA (Obamacare) is legal on the basis that it's a tax. SCOTUS said so. That said; your liberty has been rooted under the auspice of saving tax dollars through the taxation of behavior. AKA, social engineering.
Examples include (but not limited to)...: Smoking, drinking, eating, exercise, calorie burning logging, who you hang with, how you vote, do you play video games, watch TV, movies, soft drinks, drugs...your genetic lineage...etc.
With ACA, you are the governments "bitch". YOU ARE A SLAVE! We all are.