(CNN) For 85 years, Social Security has been the backbone of America’s working and middle classes. Close to half of older Americans depend on Social Security for their income. The program is a lifeline for seniors caught in a vise between fixed incomes and the escalating costs of housing, food, prescription drugs and health care. It replaces lost income for workers with disabilities, and family members of breadwinners who become disabled or pass away.

Like any program, Social Security must adapt to shifting socioeconomic trends. Today, with rampant income inequality and the ensuing decline in the number of households saving money for retirement (plus the disappearance of employer-provided pensions), Social Security benefits need to be boosted to keep beneficiaries’ heads above water. The pandemic has exacerbated retirees’ financial struggles, making the need to expand Social Security even more urgent.

Unfortunately, President Trump and his advisors have dug in their heels against the program’s expansion. Another four years of a Trump presidency could be disastrous for Social Security and the millions of Americans who rely on it.

That’s why our organization is breaking with precedent and endorsing Joe Biden — the first time we’ve backed a presidential candidate in our 38-year history. Working people and seniors cannot afford benefit cuts, or even worse, to see Social Security defunded by this President.

It became evident early on in his presidency that Trump had little intention of honoring his 2016 campaign promises not to touch Social Security. Year after year, Trump’s budget proposals have called for slashing Social Security Disability Insurance (SSDI) by billions of dollars. His appointees tried to change the rules in 2019, which would make it harder for workers with disabilities to continue collecting Social Security. Worst of all, he blatantly tampered with the program’s revenue stream through his unilateral payroll tax deferral. He even pledged to “terminate” the payroll taxes that fund Social Security if re-elected.

But if that isn’t enough reason for seniors, workers and their families to deny Trump a second term, recent reporting on his business and tax history has even more alarming implications for Social Security and the 69 million Americans who depend on it. According to The New York Times, the President bankrupted multiple businesses, and wrote off billions of dollars in losses so that he paid only $750 in income taxes in 2016 and 2017. A businessman capable of such financial negligence may do the same thing to Social Security if given a second term in the White House. It will be business as usual, the Trump way, as he bankrupts the program and leaves working people and retirees out in the cold.

For years, conservatives have falsely claimed that Social Security will inevitably run out of money. While it’s true that the Social Security trust fund reserves will be depleted by 2035 if Congress takes no corrective action, the program would not be “bankrupt,” because it still would receive revenue from workers’ payroll taxes. And, even in that scenario, it could pay nearly 80% of benefits. Not so, however, if the President were to follow through on his vow to “terminate” payroll taxes, choking off Social Security’s main funding stream. In that case, Social Security truly could go bankrupt.

Social Security’s chief actuary estimated that if payroll taxes were terminated (as the President has threatened), and the revenue not replaced by other funds, the program would run out of money by mid-2023, unable to pay any benefits. Imagine what that would do to the millions who have earned their benefits and depend on Social Security for basic financial stability. Coupled with the loss of tax revenue these benefits provide to state and local governments, defunding Social Security would hurt the small businesses where seniors spend their benefits.

Trump doesn’t seem opposed to cutting benefits, either. Earlier this year, he said he’d take a look at them. That means that even if he doesn’t bankrupt the program, the President might be open to cutting retirees’ already modest benefits.

Meanwhile, Biden has called Social Security a “sacred obligation.” He has a plan to boost Social Security benefits for poorer and older retirees. And he supports lifting the annual payroll wage cap (currently set at $137,700) so that high earners like Trump finally pay their fair share.

A President Biden and a Democratic Congress could address Social Security’s long-term financial health in a way that helps, not hurts, retirees, people with disabilities and survivors. They could enact Rep. John Larson’s Social Security 2100 legislation endorsed by our organization, which would guarantee the program’s solvency beyond the end of the century while boosting benefits and adopting a fairer index for calculating annual cost of living adjustments.

The choice for voters who support Social Security could not be more stark. By electing Biden, Americans who pay into Social Security their entire working lives can rightly expect that the program will not only endure, but be expanded and strengthened. On the other hand, there is no reason for voters to continue to leave Social Security in the hands of a President who has no compassion for the people left in the lurch. Before he runs Social Security into the ground like he did with his businesses, let’s refuse to renew our contract with Trump.

View article on CNN.com.