“Before welfare reform, you had, in the minds of most Americans, a stark separation between the deserving working poor and the undeserving welfare poor,” Barack Obama said in 2008, explaining why he supported the welfare law enacted under President Bill Clinton. “What welfare reform did was desegregate those two groups. Now, everybody was poor, and everybody had to work.”

Yet as earnings for many working-class families have stagnated or stumbled despite nearly eight years of recovery, resentment about the size and cost of the social safety net has grown. That fed the wave of anger that helped propel President Trump into the White House. The greatest disdain is directed toward adults who seem capable of working.

The mentally ill, older adults and disabled people can do little to take care of themselves, Mr. Carson said, but “there is another group of people who are able-bodied individuals, and I think we do those people a great disservice when we simply maintain them.”

Mr. Carson echoed the views of Speaker Paul D. Ryan, Republican of Wisconsin, who argues that government assistance has done more harm than good.

“Ryan revived the idea that these programs hurt people rather than help them, that dependency is bad,” said Robert A. Moffitt, an economics professor at Johns Hopkins University.

Yet defining public assistance as inherently counterproductive denies the possibility that there may be a trade-off between values and effectiveness.

Both liberal and conservative researchers agree that tax credits, food stamps, child care support and Medicaid reduce hunger, illness and poverty among the poorest Americans.