IN advance of St. Patrick’s Day, I went time traveling, back to the 1840s and Ireland’s great famine. On one side of the Irish Sea was Victorian England, flush with the pomp and prosperity of the world’s mightiest empire. On the other side were skeletal people, dying en masse, the hollow-bellied children scrounging for nettles and blackberries.

A great debate raged in London: Would it be wrong to feed the starving Irish with free food, thereby setting up a “culture of dependency”? Certainly England’s man in charge of easing the famine, Sir Charles Trevelyan, thought so. “Dependence on charity,” he declared, “is not to be made an agreeable mode of life.”

And there I ran into Paul Ryan. His great-great-grandfather had fled to America. But the Republican congressman was very much in evidence, wagging his finger at the famished. His oft-stated “culture of dependency” is a safety net that becomes a lazy-day hammock. But it was also England’s excuse for lethal negligence.

There is no comparison, of course, between the de facto genocide that resulted from British policy, and conservative criticism of modern American poverty programs....