By Byron York

Chief Political Correspondent

for The Washington Examiner.

When it comes to the politics of Obamacare, there's really only one question that matters: How many Americans are benefiting from the new health care system, and how many are hurting? Problem is, we know more about the first part of the question than the second.

Obamacare's advocates have pushed hard against Republican attempts to highlight Americans who have been particularly hard hit by the new law. "There's plenty of horror stories being told," Senate Majority Leader Harry Reid said in February. "All of them are untrue."

Those advocates have hit back so hard that it appears they are trying to discredit the notion that anyone has been hurt by the system. "I'm beginning to think there's not actually a single person in America who's been harmed by Obamacare," Mother Jones' Kevin Drum wrote in February.

So who has, in fact, been harmed by Obamacare? The first question, of course, is what "harmed" means. But let's define it as anyone who faces higher premiums, or higher deductibles -- adding up to a total higher cost -- and/or a narrower choice of hospitals, doctors and prescription drugs than they had before. For them, health care is a more expensive and troublesome proposition than it was before Obamacare.

Everything we know about the system suggests there are millions of Americans in that position, but how many? "There is no hard number," says health care analyst Bob Laszewski. The reasons are as complicated as Obamacare itself.

"When carriers converted their old policies to Obamacare-compliant, it was typical for the insurance company to increase costs about 35 percent to comply," Laszewski says. "That increase could come in the form of higher premiums, more co-pays and deductibles, and narrower networks. A carrier might have only increased rates 15 percent but then created a narrow network worth another 25 percent, for example. Even when they did the above, some individuals might have seen a 15 percent decrease and others a 50 percent increase -- many demographic issues skewed the rate result. So, getting any simple 'it went up 34.7 percent' answer just isn't possible."

The bottom line, according to Laszewski: "We have literally millions of people each impacted a bit differently." That's hard to quantify and turn into a neat political argument.

We know more about Obamacare's beneficiaries. First there are the roughly 3 million low-income people added to the Medicaid rolls (even though it is not clear how many would have qualified for the program had Obamacare never existed). In any event, they have coverage -- if not actual quality health care -- and it's all paid for by the taxpayers.

Then there are the people who receive federal subsidies to buy health coverage through Obamacare's exchanges. When President Obama announced recently that 8 million people have "signed up" for coverage through the exchanges, that means perhaps 6.5 million have actually paid for it. And only some of them receive taxpayer-paid subsidies: In late March, the Kaiser Family Foundation estimated that "3.5 million people have qualified for a total of about $10 billion in annual premium subsidies, or an average of about $2,890 per person."

Add to that young people who are now remaining on their parents' coverage until age 26, the fairly small number of people who were in the past denied coverage because of a pre-existing condition, and others who in some way have a better deal under the new system, and you have the universe of Obamacare's beneficiaries.

How does that compare to the number of people who have gotten a bad deal from Obamacare? It's impossible to know right now, and that makes it impossible to make much of a political calculation.

Even what appears to be Obamacare good news can mean bad news for potential voters. For example, this week the Congressional Budget Office released a report, much noted by Obamacare supporters, announcing that the program's subsidies will cost the government less than originally forecast. But Obamacare advocates didn't dwell on how that came about.

"The plans being offered through the exchanges in 2014 appear to have, in general, lower payment rates for providers, narrower networks of providers, and tighter management of their subscribers' use of health care than employment-based plans do," the CBO said. "Those features allow insurers that offer plans through the exchanges to charge lower premiums (although they also make plans somewhat less attractive to potential enrollees)."

Look at the phrase "tighter management of their subscribers' use of health care." Does that sound like something that will satisfy millions of patients -- or set off renewed fears of rationing?

And of course, on the Obamacare losers side, don't forget the people and businesses paying significantly higher taxes to pay for the program.

Will people who pay more, or who get less, or both, take their Obamacare unhappiness out against Democrats this November? Some surely will. But how many, and how strongly motivated they will be, will probably remain unknown until after the polls have closed.