In the period between when most provisions of Obamacare were implemented in 2014 until 2020 (when the Covid-19 pandemic began), average U.S. life expectancy had a net change of zero. This runs contrary to the modern norm of rising lifespans and was the worst six-year period in the U.S. since World War II. Correlation does not prove causation, so Obamacare may not be the root cause of this stagnation, but it either hurt, failed to help, or was overwhelmed by other factors. Moreover, supporters of the law routinely used such correlations to promote Obamacare and impugn the U.S. healthcare system. They also claimed that Obamacare would be "an absolute game changer" for substance abuse, but drug overdose deaths accelerated in the wake of the law.