Boston College researchers say the Cassidy-Kaine Social Security plan would fail to cover its added debt about 64% of the time, even if the investment fund earned a 6.5% real return. That finding cuts straight into the proposal’s promise: keep benefits intact without raising taxes or forcing immediate cuts.
The plan tied to Bill Cassidy and Tim Kaine would have Washington borrow $1.5 trillion to seed a stock-heavy fund, then borrow another $25.1 trillion over 75 years to cover the gap between Social Security revenue and promised benefits. Put together, that is $26.6 trillion in new borrowing, a scale that makes the numbers as important as the politics.
The reason the latest warning is landing now is simple. Social Security’s trust fund is expected to run out of money sooner than previously thought, and benefits could face a 22% cut by 2032 unless lawmakers act. That has put every rescue idea back under a harsher light, especially one that depends on Wall Street returns and still asks the federal government to take on more debt.
In last month’s report, Anqi Chen, Alicia Munnell and Jean-Pierre Aubry said the gamble does not always pay off. Their simulations found that even under the plan’s own 6.5% assumption, investment returns would miss the extra debt load in most runs; when the assumed real return drops to 4% a year, the fund fails 83% of the time. The researchers also noted that the debt burden would land on top of a federal balance sheet already carrying $39 trillion in debt, with publicly held debt at 100% of GDP.
That is the part the plan cannot smooth over. It is designed to spare recipients from benefit cuts and taxpayers from higher payroll taxes, but the borrowing has to be repaid somewhere, and the report says that the extra debt could itself push rates and market conditions in the wrong direction. If the stock fund underperforms, the government is left not with a rescue but with a larger debt bill and interest costs after 75 years.
There is no confirmed next step for the proposal, but the unanswered question is no longer whether Social Security needs a fix. It is whether a rescue that depends on borrowing trillions more and trusting equity markets can survive the math that was just run against it.
