It's mid-April, and Karlyn Bowman — the astute public opinion analyst at the American Enterprise Institute, a think tank located in Washington — has noticed something significant. Tax Day "comes and goes without a ripple," she recently wrote. There's not much fuss.

Discontent with the income tax has ebbed. To buttress the point, Bowman cited intriguing survey data. A recent Gallup Poll found that only 1 percent of Americans rated taxes the nation's top problem.

In a Pew poll, respondents ranked "reforming" the tax system 16th out of 24 problems. Indeed, Gallup reports that roughly half of Americans think their income-tax burden is about right.