WASHINGTON – President Trump waded back into the immigration battle Wednesday, touting a plan by two Republican senators designed to slash legal immigration and block the entry of low-skill, low-wage workers into the United States.

Proclaiming the proposal to be the biggest overhaul of immigration in more than half-a-century, Trump said the current system "has not been fair" to U.S. workers because it allows employers to undercut them by hiring migrants for less pay.

"This legislation demonstrates our compassion for struggling American families who deserve an immigration system that puts their needs first and that puts America first," Trump said during a brief White House event.

Republican Sens. Tom Cotton of Arkansas and David Perdue of Georgia, who introduced similar legislation in Congress earlier this year, joined Trump at the announcement.

The bill, designed to cut legal immigrants into the United States by 50% over ten years, has been stalled in the Senate for months.

At the heart of their proposal is an attempt to completely overhaul the focus of the U.S. immigration system, which currently favors immigrants who have family ties over those who must prove they will contribute to the economy.

It reduces the 1.1 million permanent immigrants accepted each year by allowing U.S. citizens to sponsor only their spouse or child, eliminating diversity lottery visas and limiting the number of refugees offered permanent residency in the country.

The plan would change the green card system "towards people who can speak English, who have high degrees of educational attainment, who have a job offer that pays more than a typical job in their local economy, who are going to create a new business, who are outstanding in their field around the world," Cotton said.

Perdue said the plan is based partly on that of Canada, where 63% of legal immigrants are admitted based on their potential contributions to the economy, and only 24% are admitted based on family ties. The U.S. system is flipped, with 63% of legal immigrants admitted based on family ties and 13% based on their economic potential.

Critics, including many members of Congress, said the plan calls for allowing immigration based on ratios of applicants and a points-based system of approvals, not hard numbers.

That means it will wind up reducing legal immigration, whether applicants are skilled or not.

"The Perdue-Cotton bill does exactly what President Trump has indicated he does not want to do, and that is massively restrict legal immigration," said political consultant Liz Mair, who describes herself as a Republican immigration advocate.

Mair disputed Perdue's comparisons of his plan with those of Canada and Australia, saying, "both of those countries admit massively more legal immigrants relative to their population than the U.S. ever could if this bill became law."

In getting behind the plan, Trump – who made immigration a major campaign issue – said he wants a "merit-based system" that reduces green cards for low-skill workers and emphasizes migrants who can speak English and have technical skills.

That seems to run contrary to his actions as president thus far.

Shortly after taking office, Trump announced a program-wide review of the H-1B visa program designed for high-skilled foreign workers trained in science, technology, engineering and mathematics. Trump said the program was being abused by technology companies as they imported cheaper foreign workers to replace U.S. tech workers.

Then, two weeks ago, Trump's Department of Homeland Security announced that it would create 15,000 additional H-2B visas that are designed for low-skilled workers, including those who work in retail, construction, restaurants, hotels and resorts, including those run by the Trump organization.

It's unclear how the renewed push for the legislation – even with Trump's support for it – will fare in the Senate.

Sen. Ron Johnson, R-Wis., told reporters at the Capitol Wednesday that he supported skilled-based immigration but the U.S. also needed other kinds of workers.

“If Wisconsin is an indication of the rest of the country, we’re short workers,” the conservative senator said. “We need migrant laborers to milk our dairy cows. I haven’t looked at the numbers but my sense is that is probably policy (that) is going to harm economic growth."

And Sen. Lindsey Graham, R-S.C., said the proposal would be "devastating" to his state's economy, which relies on an immigrant workforce.

“I've always supported merit-based immigration. I think we should always want to attract the best and brightest to the United States," he said. “Unfortunately, the other part of this proposal would reduce legal immigration by half, including many immigrants who work legally in our agriculture, tourism and service industries."

Since South Carolina’s number one industry is agriculture and tourism is number two, he said, "if this proposal were to become law, it would be devastating to our state’s economy which relies on this immigrant workforce."

What's more, Democrats are not likely to support a fundamental change to the nation’s family reunification policy for legal immigration.

Shortly after Trump's appearance, Democratic National Committee Chair Tom Perez released a statement in both English and Spanish.

“Donald Trump and Mike Pence keep pushing their anti-immigrant agenda, and now they’re seeking to deny millions the American Dream by dramatically cutting legal immigration and limiting family reunification," he said.

"Instead of catching criminals, Trump wants to tear apart communities and punish immigrant families that are making valuable contributions to our economy. That’s not what America stands for. We need comprehensive immigration reform that tackles the real issues with our immigration system and reflects the views of the vast majority of Americans who favor a legal path to citizenship for those already in our country.”

Contributing: Eliza Collins, Erin Kelly