WHO PAYS? Current estimates suggest that it would cost in the neighborhood of $1 trillion over 10 years to extend coverage to tens of millions of uninsured Americans. Under current plans, half or more of that would be covered by reducing payments to providers within the giant Medicare program, but the rest would require new taxes or revenue sources.

If President Obama and House Democratic leaders have their way, the entire tax burden would be dropped on families earning more than $250,000 or $350,000 or $1 million a year, depending on who’s talking. There is strong opposition in the Senate, and it seems likely that at least some burden would fall on the less wealthy.

Many Americans reflexively reject the idea of any new taxes  especially to pay for others’ health insurance. They should remember that if this reform effort fails, there is little hope of reining in the relentless rise of health care costs. That means their own premiums and out-of-pocket medical expenses will continue to soar faster than their wages. And they will end up paying higher taxes anyway, to cover a swelling federal deficit driven by escalating Medicare and Medicaid costs.

WHO WON’T BE HAPPY? Healthy young people who might prefer not to buy insurance at all will probably be forced to by a federal mandate. That is all to the good. When such people get into a bad accident or contract a serious illness, they often can’t pay the cost of their care, and the rest of us bear their burden. Moreover, conscripting healthy people into the insured pool would help reduce the premiums for sicker people.

Less clear is what financial burden middle-income Americans would bear when forced to buy coverage. There are concerns that the subsidies ultimately approved by Congress might not be generous enough.

WHAT IF I HAVE GOOD GROUP COVERAGE? The main gain for these people is greater security. If they got laid off or chose to leave their jobs, they would no longer be faced with the exorbitant costs of individually bought insurance but could buy new policies through the insurance exchanges at affordable rates.

President Obama has also pledged that if you like your current insurance you can keep it.

Right now employers are free to change or even drop your coverage at any time. Under likely reforms, they would remain free to do so, provided they paid a penalty to help offset the cost for their workers who would then buy coverage through an exchange. Under the House reform bill, all employers would eventually be allowed to enroll their workers in insurance exchanges that would offer an array of policies to choose from, including a public plan whose premiums would almost certainly be lower than those of competing private plans.