The White House delay on the employer mandate to provide health insurance has raised questions about the readiness of the Affordable Care Act on the whole. Wonkblog’s Sarah Kliff provides insight on why the delay comes now. (The Fold/The Washington Post)

The Obama administration’s decision this week to put off a key employer requirement in its health-care overhaul energized opponents of the law, reviving the measure as a potent political issue as its backers are working to sell the public on its merits.

Conservatives pounced on the decision to give employers another year before they must provide health insurance for their employees, arguing that the move buttresses their case that the law is burdensome and fundamentally unsound. Republican leaders and major tea party organizations vowed to renew their efforts to gut the legislation.

“The White House seems to slowly be admitting what Americans already know,” said Senate Minority Leader Mitch McConnell (R-Ky.), calling once again for the measure “to be repealed and replaced.”

Administration officials cast the one-year delay, announced late Tuesday afternoon, as a sign of their responsiveness to the concerns of business leaders, who had complained that the employer mandate was costly and complicated. Other parts of the law, including tax credits for low- and middle-income Americans without employer-provided insurance and a ban on denying coverage for preexisting conditions, will go forward as planned, officials said.

“This decision won’t affect the ability of Americans to get access to affordable health-care coverage,” said White House spokesman Joshua Earnest. “What it will do is ensure that we have the time we need to implement a workable reporting system for the vast majority of companies that are already providing coverage to their employees and to companies that plan to offer new coverage.”

See how the states have sided on some of the key provisions of the Affordable Care Act.;

But with the move, the White House “sent the message that thing that is their central achievement is all messed up,” said Douglas Holtz-Eakin, president of the American Action Forum, a conservative policy group. “The clear winners here are critics of the law. It continues to be unpopular on the ground, and this just fuels the intensity.”

Republican leaders of the House Energy and Commerce Committee announced Wednesday that they plan to hold hearings on the administration’s decision, saying the delay was at odds with previous statements by officials that implementation of the law was on track.

Tim Phillips, president of the conservative advocacy group Americans for Prosperity, said his group plans to incorporate postponement of the employer mandate into a major campaign already in the works.

“It gives another messaging opportunity, because now we can tell our fellow Americans unsure about the law, ‘If it’s so good, why do they keep delaying it?’ ” said Phillips, whose group played a pivotal role in attacking “Obamacare” in the 2010 midterm elections.

In giving companies until January 2015 to provide their employees insurance, “you’ve guaranteed that this is going to continue to be an election issue,” said Michael D. Tanner, a senior fellow at the Cato Institute.

Still, the delay could also spare President Obama and other Democrats from contending with another thorny political problem in the 2014 midterms: the prospect of companies reducing staffing in order to avoid the mandate, which affects businesses with 50 or more workers.

Supporters of the health-care overhaul said Wednesday that the landscape will shift as Americans obtain new coverage through federal- and state-backed marketplaces, known as exchanges, which go into effect this fall.

“This will have a very short-term impact,” said Ron Pollack, executive director of Families USA, a nonprofit organization working to promote the law. “As people learn about how this will affect their lives, people are going to feel that this is actually helpful, and that is going to move the politics in a positive direction.”

Nevertheless, backers of the measure said the delay strengthens the need for the White House and its allies to aggressively sell the law’s benefits to the public.

“What it does do is really reinforce our conviction that the weeks and months ahead, we need to focus on the personal, rather than the political,” Pollack said. “The overwhelming majority of people who get helped by the Affordable Care Act are unaware of how it will help them. That’s our job. . . . We have got to do a really good, effective job explaining this stuff.”

Enroll America, a nonprofit group backed by hospitals and health insurance companies and run by a former White House official, kicked off a campaign last month called Get Covered America that is deploying volunteers across the country to talk up the program. Organizing for Action, the advocacy group formed by Obama advisers to back his second-term agenda, recently launched a television ad delivering the same message.

“You don’t have to explain the bill,” said Ezekiel Emanuel, chair of the Department of Medical Ethics and Health Policy at the University of Pennsylvania, who served as a special Obama administration adviser on health policy and is the brother of former White House chief of staff Rahm Emanuel. “You have to explain the benefits people are going to get. They are already out there; people just haven’t absorbed them.”

Jonathan Gruber, an economics professor at the Massachusetts Institute of Technology who helped craft the bill as a consultant, said the employer requirement “is not a fundamental part of the law.”

“It’s basically a financing mechanism,” he said.

Advocates said the key now is to put in place the biggest pieces of the legislation, particularly the exchanges that will allow Americans to shop for the best insurance coverage.

“There is no way that any big new program is flawless,” Pollack said. “But it is absolutely essential that there is a delivery on the key benefits that will make a big difference in people’s lives.”