The nation’s health reform law — applauded by many for its long-overdue changes and derided by others for going too far or not far enough — turns 2 today.

After two politically noisy years contesting the measure, even this milestone isn’t passing quietly. Just last night, the House voted to undo a key provision of the law, scrapping a yet-to-be-appointed board that would advise the government on finding savings in the Medicare program. And the House budget resolution, which essentially repeals the law, is slated for a floor vote next week.

Despite the controversy, there’s no denying that the measure has dramatically altered the health landscape.

“In the last two years, we have seen a tectonic shift in our approach to health in this country,” said Georges Benjamin, executive director of APHA, in a news release marking the anniversary. “Not only are we expanding access to care for millions of Americans, we are transforming our health system to elevate prevention and wellness as a primary goal.”

Chiefly, the law’s Prevention and Public Health Fund marks an historic investment in public health and community-based prevention. The fund supports preventive health screenings and efforts to address chronic diseases such as obesity, heart disease, cancer, chronic lung diseases and tobacco use. It also strengthens state and local public health infrastructure by supporting workforce training, data collection and analysis, and necessary equipment and tools, and it supports critical clinical and community-based prevention programs.

“The Prevention and Public Health Fund will help communities make policy, environmental, programmatic and infrastructure changes to ensure that healthy choices are the easy choices for America’s families,” wrote Jeff Levi, executive director of Trust for America’s Health, recently on the Health Affairs Blog.

The Affordable Care Act has ushered in other life-saving benefits that are already a reality for millions of Americans. All health plans are now required to allow children to remain on their parents’ plans until age 26, a move that has enabled 2.5 million young adults to gain health insurance, and, according to a new report from the U.S. Department of Health and Human Services, retain their coverage.

The law bans health plans from imposing lifetime benefit limits and denying coverage to young people due to a pre-existing condition. It also requires health plans to cover the cost of preventive services rated A or B by the U.S. Preventive Services Task Force, such as recommended vaccines and preventive care and screenings for women. According to HHS, 86 million Americans received at least one free preventive benefit in 2011.

Even with expanded protections and benefits, the public remains divided over the measure. According to a March poll from the Kaiser Family Foundation, 41 percent held a favorable view of the Affordable Care Act while 40 percent viewed it unfavorably. As seen in prior polls, however, the majority of Americans tends to favor provisions in the law that they were not aware of once they are explained to them, such as tax credits to small businesses, the ability to appeal health plan decisions and no cost-sharing for preventive services.

The measure faces its biggest hurdle on Monday when the Supreme Court begins hearing three days of arguments on the law’s constitutionality. The provisions being challenged by both private interests and a number of states include the individual mandate that would require most Americans to obtain health insurance and the requirement that states cover uninsured individuals by expanding eligibility for their Medicaid programs.

APHA has joined other health groups in submitting briefs in support of the law. A decision in the case is expected at the end of the court’s term in late June.

While the long-term fate of the Affordable Care Act hangs in the balance, it is the law of the land and leaves many advocates hopeful and determined to achieve its potential.

“Today, we celebrate the two-year anniversary of the Affordable Care Act. Tomorrow, we roll up our sleeves and get back to work,” said Benjamin.

To view a timeline of health reform’s major milestones, visit Kaiser Health News.