Both liberals and conservatives believe they are seeing the light at the end of the tunnel with the Affordable Care Act. With the HealthCare.gov Web site running more smoothly, liberals are confident that Obamacare will soon be entrenched. Just as Republicans in the 1950s came to accept Social Security to avoid electoral defeats, ACA supporters insist that conservatives are courting political disaster if they continue to oppose the law. Republicans have a different perspective. They point to millions of cancelled insurance policies, ongoing enrollment problems, and repeated implementation delays as signs that the law is on the brink of collapse. The ACA remains fundamentally flawed, they claim, and all these Band-Aid improvements will never repair a program that was defective from the start.

But what do we really know about the dynamics of “policy entrenchment”— that is, whether programs survive after Congress creates them? There are a lot myths and half-truths circulating in our national dialogue about ACA.  It’s time to take stock of what political science research actually tells us.

Myth 1: Government programs never die.

Given how difficult it is to revise an existing law, it might seem that a program’s entrenchment is assured once it has been enacted. In his 1976 book “Are Government Organizations Immortal?” political scientist Herman Kaufman argued that “government activities tend to go on indefinitely.” More recent research demonstrates, however, that policy entrenchment has limits. According to a study by Christopher R. Berry, Barry C. Burden and William G. Howell, a spending program has a 1 percent chance of death every year in its first 10 years of life, after which the probability of termination slowly begins to decline. New policies are trial and error affairs, and they don’t always pan out. Programs can be killed. An example is the Medicare Catastrophic Coverage Act of 1988, which Congress terminated in 1989 when senior citizens soured on the measure. Short of formal repeal, programs can simply fade away, as did Lyndon Johnson’s Model Cities initiative and Richard Nixon’s revenue-sharing program. The main danger the ACA faces is not outright repeal, but the gradual whittling away of its subsidies, regulations and tax provisions....