"…the landmark social welfare program of a generation…"

Steady on. The real irony here is that Obamacare is really Romneycare. 

Democrats, or at least those who were not owned by the insurance industry, initially wanted a single-payer model for health care not unlike Canada's. However, when it became clear early in Obama's mandate that that was not going to happen, Democrats pivoted back and proposed instead a version of the moderate Republican approach to healthcare, which was based on the program developed by Romney when he was Governor of Massachusetts.