At a time of unprecedented income inequality and economic instability, Social Security has become a major flashpoint in the presidential election -- and for good reason. After all, despite promises to the contrary during his 2016 campaign, President Donald Trump recently floated the idea of cuts to the program.

This is a major threat to all 64 million Social Security recipients -- and particularly to communities of color. Almost three quarters of African American and Latino beneficiaries rely on Social Security for the majority of their income, and without Social Security, roughly half or more elderly Latinos and African Americans would be living in poverty.

Trump, however, is not the only reason we should be concerned about the future of Social Security: Bloomberg News' congressional correspondent recently reported that Republican Senate leader Mitch McConnell "told me he hopes to work with the next Democratic president to trim Social Security, Medicare, Medicaid."

All of this underscores an important reality: to both defeat Trump in this election and strengthen Social Security, we must choose Bernie Sanders as our Democratic nominee, because he has an unwavering record fighting against Social Security cuts -- and fighting for an expansion of the program.

Unfortunately, not every candidate in this race has such a track record.

Former Vice President Joe Biden has pushed to cut benefits in the past. He delivered a Senate floor speech in 1995 boasting that he had tried four separate times to freeze funding for Social Security, Medicare, Medicaid and veterans benefits. And as recently as 2007, he said Social Security cuts should be on the table.

Former New York Mayor Michael Bloomberg has an even more troubling record. He co-chaired a business group that pushed to cut Social Security. In that role, he appeared on national television to declare that President Obama should seek a deal with McConnell that featured "intelligent cuts."

"There is a way to slowly decrease the benefits or raise the eligibility age for Medicare and for Social Security," Bloomberg said. "There's a way to have more co-pay on Medicaid which will do two things: one, the users of the service will pay a little more. But two, they'll think twice before they use services."

That is exactly the kind of record Trump would seize on in a general election -- and it is the kind of deal McConnell wants from the next president.

Senator Sanders has a much different record -- one that would not be susceptible to those Trump's attacks, and one that would tell McConnell he will never get the cuts he so desperately wants.

Throughout his career, he has always fought to protect Social Security. During his first successful run for Congress, he campaigned against freezes or cuts to cost-of-living adjustments for Social Security recipients. Within weeks of being sworn in as a member of the U.S. House, he was one of just 27 House lawmakers to co-sponsor a bill to increase Social Security benefits for caregivers. He also co-sponsored legislation to block a cut in Social Security benefits for survivors -- and he repeatedly opposed balanced budget amendments from Republicans and conservative Democrats that also would have cut Social Security.

As a U.S. Senator, he continued this advocacy. He worked with Democratic lawmakers to convince the Obama administration to oppose efforts to cut Social Security -- and to instead support an expansion of Social Security.

Senator Sanders is the author of legislation to do just that.

Today, billionaires pay the same amount of money into Social Security as someone who makes $132,900 a year. Sanders' legislation lifts that cap, and applies the payroll tax to all income over $250,000. The new revenue generated by that change would not only make Social Security solvent for the next 50 years, it also would allow us to expand benefits across the board, and increase cost-of-living adjustments to keep pace with inflation.

When President Franklin Roosevelt signed the original bill creating Social Security in 1935, he called it "a law that will take care of human needs and at the same time provide the United States an economic structure of vastly greater soundness."

Eighty-five years later, we must now fortify that economic structure: we must defeat Trump and elect Bernie Sanders -- whose record makes clear he will build on Roosevelt's historic achievement.

Nina Turner is a former state senator from Ohio, and a co-chair of the Bernie Sanders campaign.