“Chained CPI” might sound technical and boring, but anyone who has closely followed the Social Security debate knows better. It has long been proposed as a deceptive, hard-to-understand way to cut our earned Social Security benefits.

Donald Trump’s recent budget proposal included billions of dollars in Social Security cuts. The proposed cuts were a huge betrayal of his campaign promise to protect our Social Security system. Fortunately for Social Security’s current and future beneficiaries, he has little chance of getting these cuts past the House of Representatives, which is controlled by Democrats.

So Trump and his budget director/chief of staff Mick Mulvaney, who has long been hostile to Social Security, are trying another tactic to cut our earned benefits. They are pursuing a long game to reach their goal. In a divide-and-conquer move, the focus is not Social Security. At least, not yet.

Last week, the Trump administration revealed that it is planning to employ the so-called chained Consumer Price Index (CPI) in a way that does not need congressional approval. “Chained CPI” might sound technical and boring, but anyone who has closely followed the Social Security debate knows better. It has long been proposed as a deceptive, hard-to-understand way to cut our earned Social Security benefits.

Trump plans to switch to the chained CPI to index the federal definition of poverty. If he succeeds, the impact will be that over time, fewer people will meet the government’s definition of poverty—even though in reality, they will not be any less poor. The definition is crucial to qualify for a variety of federal benefits, including Medicaid, as well as food and housing assistance. The announcement was written blandly about considering a variety of different measures, but anyone who knows the issue well can easily read the writing on the wall.

So, what does this have to do with Social Security? Like the poverty level, Social Security’s modest benefits are automatically adjusted to keep pace with inflation. If not adjusted, those benefits will erode, slowly but inexorably losing their purchasing power over time. These annual adjustments are already too low, but they are better than no adjustment at all. The chained CPI would make these adjustments even less adequate.

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