In his most sweeping decision since taking office a week ago, Trump, a Republican, put a four-month hold on allowing refugees into the United States and temporarily barred travelers from Syria and six other countries.
The ACLU has vowed to continue fighting on behalf of those facing deportation or who are being barred from entering the country, leading to a wave of donations.
Yahoo News reported ACLU membership rose from 400,000 to more than 1 million since the election.
I've never seen anything like this. "I want to stand with them in whatever way I can".
ACLU's national director, Faiz Shakir, added that the ACLU is determined to win this legal battle.
It will be organizations like his, focused on defending civil liberties, that will be at the forefront of the pushback against Trump's agenda, Romero said. When you think about what went into the selection process for signing that executive order, that's extremely alarming.
Trump issued the statement as hundreds of protesters marched in Washington and in other cities across the country to protest the president's self-described "extreme vetting" - which resulted this weekend in dozens of foreign visitors and some legal permanent US residents being detained at domestic airports.
A federal judge in Brooklyn, New York issued an emergency stay on Saturday that temporarily blocks the USA government from sending people out of the country after they have landed at a US airport with valid visas. "Fifth Amendment procedural and substantive due process rights".
Sia promised to match donations to the ACLU, and others followed.
The American Civil Liberties Union broke all its fundraising records this weekend as it became the main group challenging President Donald Trump's immigration restrictions. If you don't remember Obama's 2011 executive order - the administration did not publicize it - it involved slowing down the approval of new visas for Iraqi nationals, following investigative findings that two Iraqi refugees were implicated in making improvised bombs targeting US troops in Iraq.
The United States' Syrian refugee program accepted more than 12,000 Syrians into the United States previous year. Critics charge that it amounts to a "Muslim ban", while Trump and his team have maintained that the order is not created to target any specific religion and is merely aimed at terror-prone nations.