– As ethical questions threaten the Environmental Protection Agency administrator, Scott Pruitt, President Donald Trump has defended him with a persuasive conservative argument: Pruitt is doing a great job at what he was hired to do, roll back regulations.

But legal experts and White House officials say that in Pruitt’s haste to undo government rules and in his eagerness to hold high-profile political events promoting his agenda, he has often been less than rigorous in following important procedures, leading to poorly crafted legal efforts that risk being struck down in court.

The result, they say, is that the rollbacks, intended to fulfill one of the president’s central campaign pledges, may ultimately be undercut or reversed.

“In their rush to get things done, they’re failing to dot their i’s and cross their t’s. And they’re starting to stumble over a lot of trip wires,” said Richard Lazarus, a professor of environmental law at Harvard. “They’re producing a lot of short, poorly crafted rule-makings that are not likely to hold up in court.”

Six of Pruitt’s efforts to delay or roll back Obama-era regulations — on issues including pesticides, lead paint and renewable-fuel requirements — have been struck down by the courts. Pruitt also backed down on a proposal to delay implementing smog regulations and another to withdraw a regulation on mercury pollution.

The courts, for instance, found that the EPA had ignored clear legal statutes when they ruled that Pruitt had illegally delayed a regulation curbing methane emissions from new oil and gas wells and that the agency had broken the law by missing a deadline last year to enact ozone restrictions.

One of the chief examples cited by Pruitt’s critics came this week when the EPA filed its legal justification for what is arguably the largest rollback of an environmental rule in the Trump administration: the proposed undoing of an Obama-era regulation aimed at cutting pollution of planet-warming greenhouse gases from vehicle tailpipes.

Pruitt made his case for the rollback in a 38-page document filed Tuesday that, experts say, was devoid of the kind of supporting legal, scientific and technical data that courts have shown they expect to see when considering challenges to regulatory changes.

About half the document consists of quotations from automakers laying out their objections to the rule. By comparison, the Obama administration’s 1,217-page document justifying its implementation of the regulation included technical, scientific and economic analyses justifying the rule.

Environmental groups have welcomed Pruitt’s court losses. Joanne Spalding, chief climate counsel for the Sierra Club, said she was pleased by what she called “sloppy” and “careless” EPA legal work. “It’s fine with us,” she said. “Do a bad job repealing these things, because then we get to go to court and win.”