Two Republican senators announced legislation Tuesday that could effectively cut legal immigration in half, marking a shift in the debate as President Trump focuses more on curbing illegal immigration.

The bill by Sens. Tom Cotton, Arkansas, and David Perdue, Georgia, would reduce the number of green cards issued annually from 1 million to 500,000.

“The net effect is to cut American immigration in half,” Cotton told Fox News’ “Fox & Friends.”

With the exception of his controversial order suspending the refugee program and travel to the U.S. from seven mostly Muslim countries, Trump largely has focused his immigration policy on calls for a border wall and more immigration agents to stem the flow of undocumented residents.

Cotton argues that issues such as illegal entry, border security and immigration enforcement are important but that the country also has to address the impact of legal immigration on U.S. workers.

“Right now, we have a legal immigration system that’s not working for American workers,” he said. “Blue-collar workers, people working with their hands, on their feet, have seen their wages stagnate for decades.”

Cotton has been among Trump’s earliest and most loyal Capitol Hill supporters.

His and Perdue’s efforts to address legal immigration is a potentially contentious issue among Republicans, considering the party’s pro-business or so-called Chamber of Commerce wing has essentially supported more workers into the country to fill jobs.

Cotton argues such policies put “downward pressure” on blue-collar wages. His bill, if signed into law, would cut legal immigration by 40 percent in the first year and by 50 percent over 10 years.

“We are taking action to fix some of the shortcomings in our legal immigration system,” Perdue said. “Returning to our historically normal levels of legal immigration will help improve the quality of American jobs and wages.”

The Reforming American Immigration for Strong Employment, or RAISE, Act would reduce green cards (for permanent legal residents) by limiting whom U.S. citizens can sponsor, ending the U.S. Diversity Visa Lottery for countries that have few American immigrants and cutting the number of refugees allowed into the United States.

Democratic Sen. Jeanne Shaheen, New Hampshire, called the legislation “senseless” and a “job killer.”

“This legislation sends a terrible message to the rest of the world and is unquestionably a job killer,” she said. “As a nation of immigrants, this bill runs counter to our values.”

Alabama GOP Sen. Jeff Sessions, expected later this week to be confirmed as U.S. attorney general, was a leading Capitol Hill voice in the effort to curb legal immigration to protect American workers.