This is what ObamaCare does: It threatens with a fine the person who fails to make a contract with an insurance company.
"[I]n the freedom of choice there ought to be a kind of equality between the contracting parties. ...[N]o fear should be unjustly inspired for the sake of making the contract, or, if such fear has been inspired, that it should be removed."
-- Hugo Grotius, On Contracts, The Law of War and Peace, Book 2, 12, X (1625)