It typically takes years for presidents to kill federal regulations they dislike, but Donald Trump has found a shortcut: He’s just putting them on long-term hold. The Trump administration has stalled more than two dozen Obama-era rules, a legally questionable tactic that sidesteps the cumbersome rulemaking process.  Presidents from both parties routinely pause their predecessors’ rules, but Trump’s delays are lasting longer and reaching further—with targets including protections for student borrowers, standards for e-cigarettes, and an expansion of requirements that airlines report lost luggage. In one instance, a federal court found the approach illegal, providing fodder for future challenges. “Obama did it to Bush. Bush did it to Clinton,” said Stuart Shapiro, a Rutgers University professor who served as a White House regulatory analyst under presidents Bill Clinton and George W. Bush. “But the extent of the regulations that we’re talking about, and the political importance and the impact, is greater in the Trump administration.” Federal agencies have wide latitude to rewrite and rescind rules, but they must follow the Administrative Procedure Act, a 71-year-old law that sets out a process designed to prevent regulatory whiplash. Agencies must first formally propose revisions, justify them and give the public a chance to weigh in. Relatively small tweaks, such as a delay, can advance more quickly—but generally still require a formal notice and comment period. Trump has moved aggressively to fulfill his promise to repeal “job-killing rules.” He issued an order requiring two rules be spiked for each one created and capped the cost of new regulations. “We’re working very hard to roll back the regulatory burden so that coal miners, factory workers, small business owners and so many others can grow their businesses and thrive,” Trump said while signing an executive order addressing the issue in February. Supporters of Trump’s approach say the president is just doing what he promised by taking on overzealous regulations. The goal of trying to align government with a president’s own philosophy “is hardly uncommon,” said Dan Goldbeck, a research analyst specializing in regulations at the conservative-leaning American Action Forum.  The effort isn’t an attempted wholesale undoing of Obama-era rules, Goldbeck said. “I think the intention is to dive back into them and see if they can tweak them—and not necessarily chop them entirely,” he said. Trump’s EPA is following the law in ensuring its “actions are consistent with our core mission and statutory authority granted by Congress,” spokeswoman Amy Graham said. “Where regulations may be unjustified or overly burdensome, we will consider all legally available means to provide regulatory certainty,” Graham said. In some cases, the administration is buying time for possible rule rewrites, as with an Agriculture Department regulation governing the treatment of organically raised livestock. The department delayed the measure’s effective date by eight months and announced it was launching a formal effort to rewrite the regulation. The administration has gone further in some cases, indefinitely delaying all or parts of rules while contemplating revamping them. They include a Federal Highway Administration mandate that local governments monitor greenhouse gas emissions and a congressionally ordered update of penalties for automakers that fail to meet fuel economy standards. “These agencies are saying they’re not going to do the job they’ve previously said needs to be done, and they’re hoping to get away with that by promising some future replacement regulation,” said William Buzbee, a regulatory law professor at Georgetown University. “This being overtly declared on so many fronts is really quite unusual.” Earlier this month, a U.S. federal Court of Appeals panel rebuked the Environmental Protection Agency for suspending a regulation requiring oil and gas companies to pare emissions of methane. A two-justice majority said the EPA wrongly claimed discretion to halt the already finalized rule, and if the agency wanted to rescind the measure, it must cite specific statutory authority to do so or go through a formal rulemaking process.  Emily Hammond, a law professor at George Washington University, said the judges were putting agencies on notice that the court would carefully scrutinize their justifications for delaying rules. The message: “You must meet statutory criteria, and if you don’t, we’ll hold what you did unlawful,” she said. The ruling is especially notable because that Washington-based appeals court hears the bulk of regulatory cases, and is poised to be the arbiter in other delay-related challenges to come. State attorneys general, environmentalists and good government activists have filed lawsuits challenging at least five other regulatory delays. Attorneys general in 18 states and the District of Columbia last week filed a lawsuit challenging a decision by Education Secretary Betsy DeVos to put on hold portions of a regulation designed to protect student borrowers who attended for-profit colleges. Just Wednesday, environmental groups filed a challenge to the EPA’s one-year delay of ozone pollution requirements. And farm workers are fighting an EPA delay of requirements that people applying certain high-risk pesticides receive training and be certified.  Challenges Filed Some factors discourage legal action: Lawsuits move slowly and, in some cases, it may take so long to litigate over a delay that the argument becomes moot. Some delays were set for 60 or 90 days, others are for a year or are indefinite. The number of delays also forces would-be challengers with limited resources to pick their battles.  To be sure, Trump’s predecessor, Barack Obama, was an active rulemaker. He finalized 90 major, economically significant regulations in his final year—some rushed through in the weeks before Trump was inaugurated. The Trump administration cites an array of legal authorities to support delays. When the Department of Transportation postponed a rule requiring more airlines report lost or damaged baggage and wheelchairs, regulators made no secret of their goal to protect airlines: “Industry is facing challenges with parts of this regulation and needs more time to implement it,” the department said. And when the EPA said it was giving farmers at least a year more to comply with the pesticide application rule, the agency blamed a staffing shortage: “EPA still has only one Senate-confirmed official,” it said in June. Reasons for Delays The Trump administration cited a provision of the Administrative Procedure Act that gives agencies limited authority to forgo notice and comment periods if there is “good cause” to find that compliance would be impractical or contrary to the public interest. And the agencies turned to a section authorizing postponements if “justice so requires” because pending litigation against the regulation is likely to succeed.  The variance suggests agencies may be trying different approaches to see what sticks, said Georgetown Law professor Lisa Heinzerling, an EPA official in the Obama administration.  “Their legal reasoning in some of these cases is so bare bones that it just seems experimental,” she said. The administration may be trying to prevent companies from spending money to comply with requirements that are destined for the trash bin. After all, power plant owners howled when they were forced to buy equipment limiting mercury pollution under a 2012 mandate only to see later that the Supreme Court order the rule be reassessed. Save Money But the rapid regulatory pivots can carry costs, too. In February, Trump’s Interior Department told companies they need not follow an Obama rule that changed how they report the value of oil and gas unearthed from public land—after it had gone into effect. Companies that had already changed their accounting systems to comply were given until August to revert back. The U.S. regulatory framework is designed to protect against just those kinds of shifts, said James Goodwin, a senior policy analyst with the liberal Center for Progressive Reform. “So much of the broader fabric of administrative law is pointed toward finality,” Goodwin said. “And once the rulemaking process has been finalized, the way you promote regulatory certainty is the process ends, and that’s when enforcement and compliance begins.”