This new Social Security math could lead us down a dangerous road

Senators Bernie Sanders and Tim Kaine have proposed a $1.5 trillion investment fund to help secure Social Security benefits for future generations. The fund would be financed through additional borrowing and invested in higher-risk assets for 75 years. While the investment fund would be able to cover about two-thirds of the projected $26.6 trillion in borrowing required to keep Social Security payments going, other measures such as raising payroll taxes or cutting benefits would still be needed to close the gap completely.

However, debt watchdogs have expressed concerns about the "dangerous, debt-funded gamble" that would come with huge risks and costs. Sens. Elizabeth Warren and Bernie Sanders have also called for lifting the cap on the Social Security payroll tax, which currently applies to a maximum of $184,500 in income. By doing so, most people would pay Social Security taxes on all of their income, but the wealthier would not.

Lifting the cap could generate more than $3.2 trillion for the trust fund over a decade, according to the Peter G. Peterson Foundation.