Obama's most significant accomplishment is generally considered to be the Affordable Care Act (ACA), provisions of which went into effect from 2010 to 2020. Many attempts by Senate Republicans to repeal the ACA, including a "skinny repeal", have thus far failed. However, in 2017, the penalty for violating the individual mandate was repealed effective 2019. Together with the Health Care and Education Reconciliation Act amendment, it represents the U.S. healthcare system's most significant regulatory overhaul and expansion of coverage since the passage of Medicare and Medicaid in 1965.