(Reuters) - U.S. President Donald Trump's temporary immigration ban faced a legal hurdle on Monday that could determine whether he can push through the most controversial and far reaching policy of his first two weeks in office.
The government has a deadline to justify the executive order temporarily barring entry to the United States of people from seven Muslim-majority countries and halting the U.S. refugee program.
A federal judge in Seattle suspended the order on Friday, opening a window for travelers from the seven countries to enter.
The government now has until 3 p.m. PST (2300 GMT) on Monday to submit additional legal briefs to the 9th U.S. Circuit Court of Appeals in San Francisco in support of Trump's order. The court is expected to act quickly, and a decision either way may ultimately result in the case reaching the U.S. Supreme Court.
The new Republican president, who has said the travel measures are to protect the country against the threat of terrorism, has reacted to challenges to his ban by attacking the federal judge in Seattle and then the wider court system.
Over the weekend, the appeals court in San Francisco denied the administration's request for an immediate suspension of the federal judge's temporary restraining order that blocked the implementation of key parts of the travel ban.
But the court did say it would consider the government's request after receiving more information.
Top U.S. technology companies, including Apple , Google and Microsoft banded together with nearly 100 firms on Sunday to file a legal brief, arguing the travel ban "inflicts significant harm on American business, innovation, and growth."
The companies noted that "immigrants or their children founded more than 200 of the companies on the Fortune 500 list."
Trump has vowed to reinstate the measures, which put a 90-day bar on citizens from Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen and a 120-day halt to all refugees.
Curbing entry to the United States as a national security measure was a central premise of his run for office, originally proposed during his campaign as a temporary ban on Muslims.
U.S. presidents have in the past claimed sweeping powers to fight terrorism, but individuals, states and civil rights groups challenging the travel order say his administration has offered no evidence it answers a threat. Protesters have taken to the street accusing Trump of discriminating against Muslims.
The government says the president is exercising his constitutional authority to control borders and that the law allows him to suspend the entry of any class of foreigners who "would be detrimental to the interest of the United States."
A businessman who had never held public office until he assumed the presidency on Jan. 20, Trump has vented his frustration over the legal challenges with a volley of attacks on the judiciary.
Ten former U.S. national security and foreign policy officials, who served under both Republican and Democratic presidents, filed a declaration in the court case arguing the travel ban serves no national security purposes.
It was signed by former secretaries of state including John Kerry, Madeleine Albright, Condoleezza Rice and former CIA directors Michael Hayden and Michael Morell.
Bob Ferguson, the Washington State attorney general who filed the Seattle lawsuit, said he was confident of victory.
"We have a checks and balance system in our country, and the president does not have totally unfettered discretion to make executive orders as he chooses," he told NBC News' "Today" show.
Trump derided U.S. District Judge James Robart in Seattle, who issued the temporary stay on Friday, as a "so-called judge."
On Sunday, he broadened his Twitter attacks on Robart, who was appointed by former Republican President George W. Bush, to include the "court system."
"Just cannot believe a judge would put our country in such peril," Trump tweeted. "If something happens blame him and court system." Trump did not elaborate on what threats the country potentially faced.
It is unusual for a sitting president to attack a member of the judiciary, which the U.S. Constitution designates as a check on the power of the presidency and Congress. Democrats seized on Trump's remarks to raise questions about how independent his Supreme Court nominee, Neil Gorsuch, might be.
"With each action testing the Constitution, and each personal attack on a judge, President Trump raises the bar even higher for Judge Gorsuch's nomination to serve on the Supreme Court," Chuck Schumer, the top Democrat in the Senate, said in a statement. "His ability to be an independent check will be front and center throughout the confirmation process."
There are numerous legal challenges still pending across the United States even as the appeals court considers the travel ban.
A federal judge in Washington, D.C. has set a hearing after two people affected by the travel ban sued. Court documents show one of them, a Somali woman married to a U.S. citizen, was allowed to enter the United States on Sunday while another, an Iranian woman married to a lawful permanent U.S. resident, is set to fly to the United States on Monday afternoon.
The Justice Department has urged Judge Tanya Chutkan not to issue a temporary restraining order. (Additional reporting by Lawrence Hurley and Susan Heavey in Washington)