Democrats and Republicans are accusing one another of trying to "cut" Medicare .

The finger-pointing obscures the reality that both parties will eventually have to make cuts to the program. It's a matter of arithmetic. The country has fewer and fewer workers available to fund the healthcare of more and more seniors.

Seniors made up only 10% of America's population in 1965, when President Lyndon Johnson signed Medicare into law. Today, nearly 1 in 5 people qualify for the program. By 2060, the number of seniors in America will have grown from 54 million to almost 95 million. And the U.S. birth rate has dropped from around 20 people per 1,000 in 1965 to 12 per 1,000 today. Medicare accounted for 13% of federal spending in 2022, net of offsetting receipts from beneficiaries' premiums and the like, according to the Peter G. Peterson Foundation . In 1972, by comparison, it was 3% of federal spending.

Absent action, the program's part A hospital insurance trust fund will be exhausted in 2028 . At that point, Medicare may not be able to pay hospitals on time — or may unilaterally cut payments to levels that reflect what the fund is taking in taxes. Either way, the financial future of hospitals would be threatened — as would Medicare beneficiaries' ability to access care.

The question for lawmakers is when and how cuts to the program will happen. It would be less disruptive to start planning now rather than waiting for the program to run out of money.

We can start by gradually raising Medicare's eligibility age from 65 to 67. That policy alone could reduce deficits by as much as $22 billion, according to the Congressional Budget Office. Changing the eligibility age wouldn't affect those who have already retired, and Americans nearing retirement would barely feel the difference. Some researchers have floated raising the eligibility age in two- or three-month increments every year, starting now. Those planning to leave the workforce in the coming decade wouldn't have to shift their plans by more than a few months.

Means testing would also cut Medicare's costs. People in their late 60s and early 70s have a median net worth of $266,400 , more than double the national median. Allocating Medicare funding based on income would ensure less advantaged seniors can afford the care they need — and avoid spending scarce taxpayer dollars on those who don't need the help.

Congress could give each senior a lump sum, tailored to their income, to spend on either Medicare or a private health plan. Since private insurers would have to compete for seniors' business, premiums would sink. A "premium support system" of similar design could have saved Medicare $419 billion dollars between 2022 and 2026, a 2017 CBO report found.

But the top line is clear: Medicare isn't sustainable on its current trajectory. Rather than humor Democrats' Medicare tactics, Republicans should explain how they'll preserve Medicare for future generations — and not let it collapse beneath the weight of this one.

Sally C. Pipes is president, CEO, and Thomas W. Smith fellow in Health Care Policy at the Pacific Research Institute. Her latest book is  False Premise, False Promise: The Disastrous Reality of Medicare for All  (Encounter 2020). Follow her on Twitter @sallypipes.