As a US Senator, Barack Obama would have found it hard to imagine health reform as a signature domestic policy of an Obama presidency to come. Indeed, when the 2008 financial meltdown hit, health care understandably took a back seat to jobs and the economy.

But President Obama couldn’t get away from health reform. Mounting evidence that the US health care system was on an unsustainable track forced his administration to make health reform its first major domestic policy initiative.

The facts were unavoidable: insurance was largely inaccessible to millions of people with pre-existing health conditions, one-in-seven Americans were uninsured, medical debt was a chief cause of personal bankruptcy, and a highly inefficient health care system was swallowing an ever-growing proportion of the US economy — over 17% at the time President Obama took office. Reforming health care became not just a priority but an economic imperative.

For more on Sabrina Corlette’s take on President Obama’s health care legacy, visit CNN.com, here.