More than 50 more tech companies signed on late Monday to a friend of the court brief trying to oppose President Donald Trump's travel ban, bringing the total number of those opposed to roughly 150.
The vast majority of those are based in Silicon Valley; the others are mostly based in New York and Southern California.
Late additions include Tesla, SpaceX, Groupon, Pandora Media, Fitbit, GoDaddy and Slack. They join companies ranging from Airbnb to Zynga, who filed an amicus brief earlier on Monday with a San Francisco appeals court earlier, all of who are arguing that the United States and their businesses are comprised of, and better off with, a welcoming atmosphere to immigrants.
Of particular note, is the signature of Tesla, based in Palo Alto, and SpaceX, based in Hawthorne, both headed by CEO Elon Musk, who is an immigrant from South Africa via Canada. Tesla relies heavily on federal tax breaks — hence the Trump administration — to make the high-priced electric vehicles more affordable. SpaceX funding depends, in part, on government contracts to deliver supplies and eventually astronauts to the International Space Station.
A SpaceX spokesman on Tuesday said via email the company has "no additional comment, and unfortunately Elon is not available for an interview."
Musk had previously said he would use his membership in Trump's advisory forum to "express out objections to the recent executive order on immigration." Musk's last tweets on the immigration issue were on Feb. 5, when he wrote, "Activists should be pushing for more moderates to advise President, not fewer. How could having only extremists advise him possibly be good?" In a second tweet, Musk wrote, "Many in America don't realize how proud they should be of the legal system. Not perfect, but nowhere is the cause of justice better served."
The legal filing follows on the heels of other actions that tech companies have taken, including a massive employee rally at Google and a $4 million donation to immigration groups; Lyft's donation of $1 million to the American Civil Liberties Union; and Airbnb's creation of a #WeAccept message during the Super Bowl.
“Immigrants are among our leading entrepreneurs, politicians, artists, and philanthropists,” the 53-page amicus brief, filed with the U.S. District Court of Appeals, states. “The experience and energy of people who come to our country to seek a better life for themselves and their children—to pursue the “American Dream”—are woven throughout the social, political, and economic fabric of the nation.”
Also late Monday, the Solicitor General's Office filed a reply to the state of Washington and others, arguing that the president alone has the power to decide who can enter or stay in the United States
The Department of Justice lawyers said Monday the travel ban was a "lawful exercise" of the president's authority to protect national security.
The three-panel court of appeals, comprising two Democrat-appointed judges and one Republican-appointed one, will hear the case at 3 p.m. PST. The oral arguments will be conducted by phone, which will be livestreamed here.
NBC Bay Area's Scott McGrew contributed to this report.