Juan Williams is a political analyst for Fox News and a columnist for The Hill.

What ever happened to the political power of Republican anger over President Obama’s health-care reform?

GOP candidates used anxiety over changes to the nation’s health-care system — which they derisively called “Obamacare” — to win big in the 2010 midterm elections. Earlier this year, it was conventional wisdom that Obama could not withstand the political rage against health-care reform in a general election.

But as the presidential campaign enters the home stretch, health-care reform is the dog that has not barked.

Polls still show that a plurality of Americans favors repealing the Affordable Care Act (ACA). But the political fury has faded. The shift in attitude comes from the flow of new benefits and discontent with the status quo in health care.

In March 2010, just before the law was passed, 37 percent of Americans approved of the ACA, and 48 percent disapproved. Today that gap has narrowed to just four percentage points, with 46 percent disapproving but 42 percent of Americans now approving of the law. More than a quarter of the people who oppose the law say they want it to do more.

According to the Kaiser Family Foundation, seven states under Republican control have said they will not begin preparing to run health-care exchanges, while 22 other GOP-run statesare preparing to offer residents comparison shopping for private health insurance by January 2014, when the individual mandate takes effect.

Another factor calming the political storm was the Supreme Court’s ruling in June that the federal mandate at the heart of the plan — requiring everyone to buy insurance — was constitutional. That decision took the fire out of a central conservative critique of the law.

The political quiet around health care is connected to the fact that Mitt Romney is — as his rival Rick Santorum said during the GOP primaries — the worst possible Republican in the country to lead an attack on Obama’s health-care reform. As governor of Massachusetts, Romney created a similar, statewide health-care system.

Romney has pledged to repeal the federal law. But in an interview this month, he said: “I’m not getting rid of all of health-care reform. Of course, there are a number of things that I like in health-care reform that I’m going to put in place.”

As items he would keep, Romney pointed to the ACA’s requirements that insurers cover people who have preexisting conditions and that young people be allowed to stay on their parents’ insurance until they are 26 or get a job.

Since that “Meet the Press” interview, Romney has not backed down from his promise to keep intact these central pillars of Obama’s health-care reform. And there has been no blowback from his fellow Republicans.

In fact, more Republicans are getting on board. Former Senate majority leader Bill Frist, a heart surgeon, recently told an interviewer: “I am supportive of exchanges and ‘Obamacare’ generally.”

Meanwhile, insurance companies and hospitals are making the argument to state governments that repeal of the ACA is highly unlikely unless an incredible landslide occurs in November, in which the GOP gains a filibuster-proof majority in the Senate and wins the White House. But at the grass-roots level, Americans who are enjoying the ACA’s new benefits understandably do not want them taken away.

The premiums of Americans enrolled in Medicare Part C (Medicare Advantage) have fallen by 16 percent since 2010, Health and Human Services Secretary Kathleen Sebelius has said.

This year, 13 million Americans or their employers who provide health insurance have received rebates from their insurance companies. That was the result of the ACA’s requirement that insurers spend 80 percent of their money on insurance, as opposed to administrative overhead and bonuses.

Last year, nearly 90 million Americans received free preventative care from their health-care provider through their insurance plans. Before the Affordable Care Act, insurance companies made customers provide a co-pay or a deductible for these often-lifesaving services.

This more welcoming attitude from Americans was clear in a poll this month by United Technologies and National Journal that asked likely voters if they thought Obama’s health-care reform would make things better or worse for each of several groups of Americans.

Forty-five percent of voters said the ACA will make life better for the middle class; 40 percent said it would make life worse.

As for Americans overall, 39 percent said the plan will make life worse in the United States, but a full 50 percent said it would make life better.

When Romney and Obama face off in next week’s presidential debate, the questions will focus on domestic policy. Two years ago, it did not seem possible that Obama would hold the upper hand on health-care reform going into that debate.