Medicaid is a federal/state partnership for government-run healthcare in which the federal government pays most of the bills and retains total control of how the program is run. When the U.S. Supreme Court ruled that ObamaCare was simply a tax instead of an unconstitutional usurpation of individual and state rights by the federal government according to the plain language of the Tenth Amendment, it slightly trimmed back the usurpation by deeming the Medicaid expansion to be each state's choice rather than a requirement as previously stated in the "Affordable Care Act."
Some states blindly jumped in to the Medicaid expansion without asking any questions. Gov. Steve Beshear abused state law to add Kentucky to that number. Others negotiated slightly less horrible deals and accepted expansion, claiming falsely to have an ability to withdraw from the expansion later if it proved too expensive.
Obama and Hillary Clinton want to keep pushing holdout states to take the Medicaid expansion by keeping alive the falsehood that states have an ability to escape it later on if they choose. Kentucky would be the first to test this if Gov. Bevin's reform proposal is rejected and he then follows through on his threat to then reverse Kentucky's entrance into expansion. The feds' interest in suckering the holdout states may well inspire them to accept at least most of Bevin's requested reforms.
If, instead, they decide to fight, Bevin could drop excess Medicaid recipients and wait for the feds to sue. Presumably, a President Trump would not fight us and President Clinton would. (Good question to ask both of them.) President Clinton would win the lawsuit, but Trump is POTUS and there is no lawsuit, Kentucky will win big by joining the states opting out of ObamaCare.