If Congress doesn’t act, more than 60 million Americans could see their Social Security income drop by nearly a quarter in six years.

That’s when Social Security’s retirement trust fund is expected to run dry, and incoming revenue would be enough to pay only 78 percent benefits, reducing every retiree’s paycheck by 22 percent.

The program, which President Franklin D. Roosevelt signed into law in 1935 during the Great Depression, is not in danger of completely running out of money. While lawmakers have long known they would need to move to close that gap — through tax increases, benefit cuts or some combination — they have been slow to act on this politically charged topic.

But the window to do that is closing.

Many of the lawmakers being elected in the coming midterms will probably be entrusted with drafting reform packages, and they will need to contemplate crucial questions: Who will absorb the costs of any changes to shore up the program, and what will the consequences be? Will people be less prepared for retirement as a result?

Procrastination has been costly, making these decisions now more difficult. Even some Republicans, who often resist any tax increases, have recently proposed raising the income ceiling on payroll taxes, the dedicated tax that finances the program, so that wealthier households contribute more.

“Any serious Social Security reform package should be scored on what it does to household retirement outcomes, not only on what it does to trust-fund balances,” said Jack VanDerhei, director of retirement research at Morningstar’s Center for Retirement & Policy Studies.

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