In February, after embarrassing himself by saying he was “not concerned about the very poor,” Mitt Romney explained that the government’s safety net would take care of them, and he promised to repair any holes in the net. That promise didn’t last very long. On Thursday, House Republicans approved, on a party-line vote, a disastrous new budget that would leave millions of struggling families desperate for food, shelter and health care — and Mr. Romney has embraced it.

The budget, developed by Representative Paul Ryan of Wisconsin, would cut $3.3 trillion from low-income programs over 10 years, according to the Center on Budget and Policy Priorities, even more than the $2.9 trillion in Mr. Ryan’s first disastrous budget last year.

“It’s an excellent piece of work,” Mr. Romney said. (Rick Santorum said it didn’t cut enough.)

The biggest of the cuts would be to Medicaid, the joint federal and state program that is already gasping for money in many states that put a low priority on health care for low-income people. Mr. Romney often talks casually about turning the program over to the states entirely and simply writing a check to dispose of a half-century federal commitment. The Ryan budget exposes just how paltry that check would be: a cut of $810 billion through 2022, one-fifth of current spending, which would lead states to drop coverage for an estimated 14 million to 28 million people.

By eliminating the expansion of Medicaid in the health care law, cutting $1.6 trillion, it would leave another 17 million low- and moderate-income people uninsured.