President Obama made an important decision Friday not to pursue discretionary new EPA regulations that would have set more stringent standards for levels of ozone in the ambient air. In a statement announcing the decision, he noted that EPA was working on revising the standard again in 2013 and concluded:

“Ultimately, I did not support asking state and local governments to begin implementing a new standard that will soon be reconsidered.”

The national ambient air quality standards (NAAQS) for ozone have a checkered history. This is the third time in as many revisions of the standard that a president has had to weigh in on EPA’s decision.

In 1997 EPA’s proposed standard of 80 parts per billion (ppb) ran into strong objections from other federal agencies, including the Department of Commerce (then led by current White House Chief of Staff William Daley) and OMB’s Office of Information and Regulatory Affairs (OIRA). President Clinton ultimately sided with EPA Administrator Carol Browner, but promised states that EPA would not actually enforce the very expensive standard — at least not right away, and not beyond some agreed-upon cost thresholds.

Ten years later, EPA again faced objections from other agencies and OIRA, as well as from state and local governments, when it proposed to tighten the standard to 75 ppb. Many regions of the country were unable to comply with the 1997 standards, so ratcheting them down again appeared unlikely to yield any health benefits but was certain to raise costs and constrain economic growth. This time, EPA also wanted to add a distinct welfare-based “secondary” standard, aimed at protecting vegetation rather than human health.

Again the interagency dispute reached the oval office, but the question to President Bush was not the appropriate level of the health standard (on which OIRA reluctantly deferred to EPA) but the addition of the welfare standard with a distinct form. EPA argued that the new form of secondary standard would not affect air quality because the primary standard was binding, but other agencies viewed it as a troubling precedent and a pointless proliferation of complicated rules. This time, the president sided with OIRA and directed EPA not to adopt a new form for the secondary standard.

Unhappy with President Bush’s decision, in 2009 disgruntled EPA staff convinced their new administrator, Lisa Jackson, to revisit the ozone standard ahead of the five-year scheduled review. In January 2010, EPA proposed not only to adopt a distinct form for the secondary standard, but also to tighten the primary standard below the level established in 2008. These new standards appeared destined to become law until the president’s announcement last week.

President Obama cited current economic conditions as part of his rationale for staying EPA’s hand on the 2011 standard. In doing so, he rejected EPA’s argument that the Clean Air Act allows no room for such considerations. The president’s decision likely will stand because environmental groups that would challenge the decision will have a stronger case by waiting until 2013, when EPA has a statutory duty to revisit the ozone standard. The threat of litigation will make it much more difficult, at that point, for any president to maintain control of the outcome.

The Clean Air Act requires the EPA administrator to set the standard at a level that is requisite to protect public health with an adequate margin of safety. “Requisite” and “adequate” leave room for judgment, but economic affordability or even feasibility are not among the factors that can be considered. By setting standards at levels that are impossible to attain, EPA seems bent on ensuring that virtually every populated area (and many unpopulated ones) is in nonattainment, so that each of us is branded a sinner. At that point the air is no cleaner, but all of us are at the mercy of EPA’s enforcement discretion; the result is that we have a government of men, rather than of laws.

President Obama took a courageous step this week in directing his EPA administrator to hold off revising the standards until 2013. But in 2013, the future will not only be in the hands of the president, whoever that may be, but also in the hands of the new Congress. Unless Congress amends the unyielding language of the Clean Air Act, unelected EPA staff will continue to ratchet down the standards and force communities throughout the country to forego productive investment and hiring decisions in order to spend hundreds of billions of dollars per year in vain attempts to meet unachievable standards.

Susan E. Dudley directs the George Washington University Regulatory Studies Center. Ms. Dudley was President George W. Bush’s chief adviser on regulatory matters.