(CNN) Sen. Bernie Sanders has a plan to add more than 50 years of sustainability to Social Security, the New Deal-era program that's facing a looming cash crunch.

The proposal would shore up Social Security with payroll taxes on income above $250,000, the Vermont independent announced Wednesday. It's the latest in a flurry of ambitious legislation being floated by lawmakers with their eyes on the 2020 Democratic presidential nomination

It is the second plan to tax the wealthy that Sanders, who previously made a 2016 runhas introduced in the last two weeks, the first targeting the estates of the richest Americans

Sanders, who's also preparing to introduce a Medicare for all proposal in the coming weeks, is looking to solidify — and boost — one of the country's most popular social safety net programs by having the rich pay more.

"At a time when more than half of older Americans over the age of 55 have no retirement savings, our job is to expand Social Security to make sure that everyone in this country can retire with the dignity they have earned and everyone with a disability can live with the security they need," Sanders said.

The Social Security Expansion Act, which Sanders first introduced in 2017, is also being introduced in the House by Democratic Rep. Peter DeFazio of Oregon. Several declared and potential 2020 Democratic candidates are co-sponsoring the legislation, including New Jersey Sen. Cory Booker and California Sen. Kamala Harris, who have announced their bids, as well as New York Sen. Kirsten Gillibrand, who is exploring a run, and Oregon Sen. Jeff Merkley, who is also considering running.

It would increase benefits for all recipients, with low-income seniors receiving a boost of nearly $1,300 a year. It would also make the annual cost of living adjustment more generous by shifting the formula to take into account health care and prescription drug costs, which rise faster than inflation.

To pay for it, Sanders would subject all income above $250,000 to the existing 12.4% Social Security payroll tax, which is split between workers and employers. Currently, the payroll tax is only applied to wages up to $132,900.

Plus, the senator would levy a new 6.2% tax on single people with investment income above $200,000 and couples above $250,000.

This extra revenue would extend the health of Social Security by 52 years, according to Sanders' office. As it stands now, the system will no longer be able to pay out full benefits starting in 2034, according to the 2018 annual report from the Social Security and Medicare trustees.

Democrats campaigned relentlessly — and successfully — in both red and blue states across the country in 2018 on a pledge to preserve programs like Social Security, which Republicans suggested could face cuts to make up for the revenue shortfalls caused by their tax cuts.

Days before the midterm election in November, Sanders laid out the stakes, tweeting: "Let us not forget that (earlier in October 2018), Mitch McConnell stated he wants to cut Medicare, Medicaid and Social Security if Republicans keep one-party rule in Washington. We must expand, not cut, these programs that are life and death for the working class in this country."

Let us not forget that just 2 weeks ago, Mitch McConnell stated he wants to cut Medicare, Medicaid and Social Security if Republicans keep one-party rule in Washington. We must expand, not cut, these programs that are life and death for the working class in this country. — Bernie Sanders (@BernieSanders) October 31, 2018

McConnell signaled in a pair of interviews weeks earlier that the Republican plan to address the deficit, which ballooned by about $2 trillion under their watch, would require reforms to Social Security, Medicare and Medicaid — the package of social programs he described as "the real driver of the debt."

Sanders slammed Republicans for saying benefits must be curtailed.

"They have their priorities backwards," Sanders said. "We're going to tax the billionaires and expand Social Security."

Lawmakers have long grappled with how to address Social Security's solvency issues. Republicans generally favor increasing the retirement age or tinkering with the formula to make payouts less generous, but President Donald Trump has promised not to touch benefits.

Democratic lawmakers in both chambers are looking to boost seniors' checks and ask the rich to pay for it. Connecticut Rep. John Larson, along with more than 200 lawmakers, last month reintroduced the Social Security 2100 Act, which would raise benefits and payroll taxes on everyone, but place an additional levy on those earning more than $400,000. It would extend Social Security's solvency beyond 2092.

Scrapping the payroll cap, however, would fundamentally change the way Social Security operates. Benefits are based on how much retirees contributed to the system while they were working, a formula that was key to the support for the law's enactment in 1935. Under Sanders' bill, the wealthy would not receive credit for the additional payroll taxes.

The proposals are the most significant effort to reshape to Social Security since former President George W. Bush tried to introduce private investment accounts into the system in 2005.