SAN FRANCISCO (CBS SF) — President Donald Trump’s push to cut legal immigration to the United States in half is being met by opposition from Silicon Valley leaders, economists, and even some Republicans senators, who all say legal immigration is key to economic prosperity.

The Trump administration Wednesday endorsed the Reforming American Immigration for a Strong Economy Act or RAISE Act, a Senate bill introduced by two Republican senators earlier this year, that aims to cut all U.S. immigration in half.

Perhaps nowhere else in the U.S. are business and political leaders more vocally opposing the bill than in California, which has more immigrants than any other state.

California, a state with 39 million people, has an immigrant population of over 10 million, according to a report from Public Policy Institute of California based on the 2015 U.S. Census Data, which is the most recent data available. Most of those immigrants are documented.

The PPIC report found that Santa Clara County had the largest percentage of immigrants, followed by San Mateo County, Los Angeles County, San Francisco County and Alameda County in 2015. While about 4.3 million California immigrants are from Mexico, census data shows that in recent years, almost twice as many immigrants have been arriving from Asia as from Latin America.

Business leaders, especially those in California’s tech industry, say the bill will stymie their ability to fill jobs and grow the U.S. economy. California’s economy is the sixth largest in the world and many attribute that success, in part, to immigration.

The Information Technology Industry Council, which represents companies including Amazon, Apple, Adobe, Dell, Facebook, Hewlett-Packard, Google, Visa, Nokia, and Microsoft railed against the bill.

Dean Garfield, President and CEO of the council said, “This is not the right proposal to fix our immigration system because it does not address the challenges tech companies face, injects more bureaucratic dysfunction, and removes employers as the best judge of the employee merits they need to succeed and grow the U.S. economy.”

California relies heavily on foreign-born individuals. Forty-two percent of California’s workers in science, technology, engineering and math (STEM) occupations were born in a foreign nation, according to an analysis of 2015 U.S. Census Bureau survey data by the American Immigration Council.

Garfield argues that the tech industry cannot find enough STEM-skilled Americans to fill open positions and that U.S. immigration policy “stops us from keeping the best and brightest innovators here in the U.S. and instead we lose out to our overseas competitors.”

TechNet, a bipartisan network of tech executives representing more than 2.5 million employees from companies such as Airbnb, Lyft, General Motors, and Paypal, among others, expressed severe opposition.

TechNet President and CEO Linda Moore said, “At this very moment, half a million jobs in the U.S. that require computer science training are unfilled. That’s indicative of the investments we need to make in STEM education as well as the need for high-skilled immigration reform that allows American companies to fill these critical labor shortages immediately.”

Moore said the RAISE Act doesn’t solve these problems and “…instead cuts green cards by half at a time when the demand for more high-skilled worker green cards and H-1B visas is holding back job creation in the tech industry.”

The bill aims to prioritize English-speaking, financially-stable applicants and shift U.S. immigration policy away from prioritizing family ties, instead emphasizing immigration based on immigrants’ job skills.

The bill would also cut refugee admissions in half.

“We look forward to an immigration structure that is better for American workers, the American economy, for American security, and better for legal immigrants and their immediate families,” said acting Secretary Of Homeland Security Elaine Duke on Wednesday.

Not all Republicans are on board, especially those in states with agricultural industries.

Sen. Ron Johnson (R-Wisconsin) said, “I’m all for merit-based and skills-based immigration, and a legal immigration system, but we need to make sure we have an immigration system that allows enough people into this country to make sure that we can staff manufacturers and dairy farms and all of our organizations that grow our economy.”

Sen. Lindsey Graham (R-South Carolina) is also a vocal opponent, arguing that his state’s top industries are agriculture and tourism.

“If proposal were to become law… devastating to SC economy which relies on this immigrant workforce,” Graham said.

California’s agriculture industry also relies heavily on foreign-born workers.

Economists don’t agree with cutting U.S. immigration either.

Over 1,400 economists wrote in an April 2017 letter to President Trump and congressional leaders, that economists of all stripes, almost universally agree on “the broad economic benefit that immigrants to this country bring.”

The letter’s signatories include Nobel laureates as well as economic advisers who served under every former U.S. president dating back to Ronald Reagan.

The bill is not expected to get enough votes to pass out of the Senate, but the White House endorsement of the bill gives Americans a clear sense of the Trump administration’s goals regarding to immigration policy.

By Hannah Albarazi – Follow her on Twitter: @hannahalbarazi.