The proposed Reforming American Immigration for a Strong Economy Act(RAISE), a plan to slash legal immigration backed by President Donald Trump, would weaken the U.S. economy over the next three decades, according to a study released today by the University of Pennsylvania’s Wharton School.

The study says that the RAISE Act, a bill recently introduced by Senators Tom Cotton and David Perdue and endorsed by President Trump on Aug 2, would reduce legal immigration while increasing the portion of new legal immigrants that are highly skilled. By 2027, Wharton’s analysis projects that RAISE will reduce GDP by 0.7 percent relative to current law, and reduce jobs by 1.3 million. By 2040, GDP will be about 2 percent lower and jobs will fall by 4.6 million. Despite changes to population size, jobs and GDP, the study continues, there is very little change to per capita GDP, increasing slightly in the short run and then eventually falling.

“If you were just to increase the skill mix of new immigrants to be 75 percent with a college degree or more then in the long run that would increase GDP by .37 percent,” said Kimberly Burham, managing director of legislation and special projects. “Where this bill is taking the hit as far as future economic growth and job growth is concerned is by reducing the total number of immigrants coming in every year. In the long run, if those immigrants had those jobs, then they would have contributed by working and by saving and there would have been more for everybody.”