Sen. Bill Cassidy (R-La.) has a message for Sen. Bernie Sanders (I-Vt.) about his plan to lift the Social Security payroll-tax cap: Do the math.
Cassidy took to X on Sunday to argue that the proposal would impose a combined 12.4% Social Security payroll tax on people "a long way from being millionaires or billionaires."
"Think of two ICU nurses married to each other," Cassidy wrote, adding that the levy would come alongside what he described as an estimated 14% tax needed to finance Medicare for All.
Cassidy was responding to Sanders, who said that expanding Social Security benefits by at least $2,400 annually and extending solvency would be priorities in his expected role as the next chair of the Social Security Subcommittee.
Sanders said his approach would involve "scrapping the cap" and requiring wealthy Americans to pay what he described as their fair share of taxes.
Under current Social Security Administration rules, payroll taxes are calculated on each worker's individual earnings, not combined household income. In 2026, the combined employer-employee Social Security tax rate is 12.4%, with each paying 6.2% on the first $184,500 earned by an individual worker.
Two Very Different Fixes for Social Security
The exchange highlights competing approaches to Social Security's financing. Sanders favors higher contributions from top earners, while Cassidy has promoted a separate investment-based strategy. In an earlier proposal, Cassidy warned that benefits could fall 28.5% within six years without congressional action. He proposed a $1.5 trillion investment fund designed to grow over 65 to 75 years.
Sanders previously argued that lifting the payroll-tax cap could extend the program's finances for decades while increasing benefits. He criticized Elon Musk over Social Security contributions, arguing that the billionaire pays the same amount as someone earning $184,500 annually because of the income cap. Sanders has proposed applying Social Security payroll taxes to earnings above $250,000, while increasing benefits by at least $2,400 annually. The proposal would leave earnings below that threshold unaffected by the additional payroll tax.
Marc Goldwein of the Committee for a Responsible Federal Budget (CRFB) questioned whether Sanders' proposal would adequately fund the program and proposed benefit increases. While saying the change could close roughly half the funding shortfall, he argued that capital gains and other investment taxes also have revenue limitations.
