This is the third of a series of occasional “Medicare Uncovered” posts that will look at how the media are covering Medicare, the nation’s vast and publicly accountable health system for the elderly, and a political target in ongoing discussions about the deficit.

The Dollar-for-Dollar Act, introduced by Tennessee Sen. Bob Corker in mid-December, aims to reduce the deficit by $1 trillion—by cutting the same amount from Medicare, Social Security, and Medicaid. Some of the bill’s provisions would significantly alter those programs.

While Congress may not pass this bill, parts of it, which have been floated by members of Congress and others, may well have legs when Beltway politicos get serious about spending priorities in coming weeks. Studying the Corker bill may help journalists get ahead of the curve. Pencils ready?

At the heart of Corker’s Medicare proposals is the goal of reducing Medicare’s costs without capping the amount the program spends overall. In other words, it would not cap spending on treatments and care. However, the burden would fall on the consumer, who will be encouraged to use fewer medical services. That means lowering costs rests on the backs of seniors who need the benefits. “All of these proposals focus on increasing out-of-pocket costs” for seniors, says Bonnie Burns, an insurance expert with California Health Advocates. “They all rest on the premise that people get too much healthcare because they don’t pay enough for it.”

Wonks who subscribe to this premise speak of making people have more “skin in the game,” making them pay more, in other words, for medical services, on the grounds that they’ll then use less of them. The National Association of Insurance Commissioners, in a recent letter to Health and Human Services Secretary Kathleen Sebelius, took a stand against the idea that seniors use more medical care when it is cheaper and recommended against making seniors pay more out-of-pocket. But the “more skin in the game” idea remains alive and well.

Those who are trying to lower Medicare’s overall costs speak of several routes to that goal. One option is to make seniors wait longer to qualify for benefits by gradually increasing the age of eligibility from 65 to 67. While they wait, seniors will have to pay for their care out-of-pocket, or buy other insurance like those offered in their Obamacare state insurance exchanges, or stay on the job longer if they can. Employers would be faced with keeping older employees and retirees on their plans longer until they can qualify for Medicare.

Another option is to make more seniors pay higher premiums for their Part B benefits that cover doctors’ visits, hospital outpatient services, and lab tests. When his bill debuted, Corker said that seniors with incomes of around $50,000 would pay higher premiums. The Obama administration embraced this general idea, floating a plan that would change the rules for determining who is eligible for the higher premiums. Under that arrangement, about 25 percent of all those on Medicare would pay more. Right now, only about five percent are paying more for Medicare. According to the Kaiser Family Foundation, Obama’s idea could mean those with incomes around $45,000 in 2012 dollars would pay more when the new rules are phased in. Now only individuals with incomes over $85,000 and couples with $170,000 pay more.

A third route to reduced Medicare costs under discussion is to eliminate the protection offered by Medigap policies that will increase the costs for those who have those plans. Again, a “skin in the game” idea. Some nine million seniors buy insurance to cover gaps in Medicare benefits. (Other seniors have similar gap coverage through retiree plans, the military, or Medicaid.) Medicare’s gaps include hospital and medical deductibles and the 20 percent coinsurance, the percentage of the bill seniors must pay.

That last one, the coinsurance, is particularly important to understand, since coinsurance is based on a percentage of what Medicare pays, not a defined dollar amount, when you use a medical service. Many people misunderstand the difference between these two methods of cost-sharing, and a percentage of the bill can result in a very large and unexpected medical expense. This is very unlike a co-payment, which is a set amount you know in advance.

Here’s what Corker has in mind:

All people on Medicare would pay what’s called a “unified deductible”—the amount a patient pays before insurance kicks in—of $550 instead of a the current separate hospital deductible ($1,184 this year) and a separate medical deductible (now $147). The new deductible would mean that people using medical services—which most do—will be exposed to an out-of-pocket cost four times higher than they have now before Medicare pays for their care.

Trudy Lieberman is a fellow at the Center for Advancing Health and a longtime contributing editor to the Columbia Journalism Review. She is the lead writer for The Second Opinion, CJR’s healthcare desk, which is part of our United States Project on the coverage of politics and policy. Follow her on Twitter @Trudy_Lieberman.