"Our mission is clear — if we want to get rid of ObamaCare, we're going to have to get rid of President Obama," Romney said, pledging that "what the Supreme Court did not do, I will do: repeal ObamaCare."

In fact, Americans are more likely to rank healthcare as a significant concern when politicians are talking about the issue. More than a quarter of Americans — 26 percent — said healthcare was the most important issue during the debate over the Affordable Care Act in the summer of 2009. (The issue had its salient moment between September 1993 and August 1994, when President Clinton was pushing for a healthcare overhaul. At the time, more in three in 10 Americans named it as their top issue.)

Last month, however, healthcare narrowly edged out "education" and "ethical/moral decline" atop Americans' worries. A quarter of Americans said unemployment was the biggest issue, and three in 10 said general economic concerns were their top priority. Dissatisfaction with the government and worries over the federal budget deficit also cracked double digits.