The U.S. Department of Homeland Security has for the third time delayed introducing its proposal for a promised major change to the controversial H-1B visa program.

Homeland Security said two years ago that in order to cut “fraud and abuses” in the H-1B program while obtaining the “best and the brightest” workers from around the world, it would change the definition of what constitutes a “specialty occupation.” The agency’s new rule would also re-define “employment” and the “employer/employee relationship.”

The agency at the time gave itself until October 2018, nearly a year, to propose the rule. But it delayed that three times, pushing ahead its timetable first by three months, then by nine months, and now to the end of this year.

Homeland Security did not immediately respond to a request for an explanation of the delays, the latest of which was revealed in the new federal rule-making agenda released this week.

John Miano, a lawyer at the Center for Immigration Studies, which advocates for reduced immigration, said the holdup probably arises in part from pressure on the government from employers using the H-1B. Miano noted that Indian outsourcers are often villainized in the H-1B debate, but major U.S. companies hire outsourcers to supply them with H-1B workers, along with employing visa holders directly. That puts the outsourcers in step with U.S. firms on the H-1B issue, he argued. “We have this kind of false division: bad Indian companies and good American companies,” Miano said. “The good American companies hire the bad Indian companies, so they don’t want anything that hinders them.”

However, Stuart Anderson, executive director of the National Foundation for American Policy, which supports expanding the H-1B program beyond the current 85,000 cap on new visas, said he believes the delays have arisen partly because federal authorities are busy developing many immigration regulations.

Also, he said, the proposed changes are complicated and Homeland Security appears to be aiming to create a rule that matches the definitions officials already appear to be using amid an aggressive crackdown that has dramatically boosted H-1B denial rates.

“They’ve been doing it without any regulations, now they’re trying to lock into what they’ve been doing through the adjudication process so that any future administration, for example, would have to undo the regulation,” Anderson said. “It’s very likely that any regulation would just kind of write out what they’ve already been doing in practice. Once you put a regulation in place … there’s a long process in getting rid of it.”

Homeland Security’s latest notification said the new rule would “better protect U.S. workers and wages,” and that the agency would add requirements to ensure employers pay “appropriate wages” to H-1B holders.

The H-1B, intended for jobs requiring specialized skills and usually at least a bachelor’s degree, has become flashpoint in America’s immigration debate and a target of the administration of President Donald Trump. Major Silicon Valley technology companies rely heavily on the H-1B, and push to expand the annual cap. Critics point to reported abuses by outsourcing companies, and argue that those companies, and tech firms bringing on H-1B contract workers to run teams of low-paid workers overseas, use the visa to supplant U.S. workers and drive down wages.

The Trump administration has dramatically increased H-1B rejection rates for outsourcing and staffing companies but has left virtually untouched the direct H-1B hiring by tech companies including Apple, Google and Facebook.

To Anderson, the administration’s move to boost H-1B rejections provides “clear evidence” that authorities are acting outside the scope of law. One sticking point in re-defining “specialty occupation” appears to be over educational requirements, Anderson said. Under federal law, for a job to be defined as a specialty occupation it must “normally” require a bachelor’s degree or higher. But U.S. Citizenship and Immigration — the agency that evaluates H-1B applications — seems to be treating such a degree as an absolute requirement when many jobs requiring specialized skills that otherwise meet the visa’s specifications don’t require one, Anderson said.

Should the rule be finalized — typically after a public-comment period — the U.S. will likely lose skilled workers to other countries with less onerous visa requirements and more certainty about work-permit laws and policies, Anderson said.

Miano disagrees. The Center for Immigration Studies supports re-defining H-1B occupation requirements to ensure that outsourcing and staffing companies aren’t using the H-1B to take jobs from U.S. workers and reduce wages by obtaining large numbers of visas and supplying foreign labor to U.S. firms at discount prices, he said. “There will be screaming that this will wipe out an entire business, but that’s a business that shouldn’t exist,” Miano said. “If a person has an ID card for Company A they would go and work in Company A’s facility every day and take direction from company A.”