US President Barack Obama claimed history and the law were on his side Tuesday, as he vowed to fight a court order freezing controversial immigration reforms.
Obama had used an executive order to bypass a hostile Congress and drive through measures to protect about four million undocumented foreigners from deportation.
But a judge in Texas issued an emergency injunction before the measures were to come into effect starting Wednesday.
Obama was defiant: "I think that the law is on our side and history is on our side, we are going to appeal it."
"This is not the first time a lower court judge has blocked something or attempted to block something that ultimately was shown to be lawful."
Twenty-six states -- all but two Republican-governed -- had pressed the Texas judge to intervene, claiming Obama had acted unlawfully.
Federal judge Andrew Hanen of the US District Court in Brownsville, Texas agreed.
"It is far preferable to have the legality of these actions determined before the fates of over four million individuals are decided," he ruled on Monday.
Immigration is a hot political issue heading towards the 2016 presidential election, around 11 million undocumented migrants in the country.
Obama's executive order would have allowed only some of them to come forward: those who have not committed serious crimes and have children who are American citizens or residents.
Obama has also tried to push more comprehensive immigration reform, which could eventually bring many millions of new voters, many seen as likely Democrats.
"This is something that we necessarily have to make choices about," Obama said again pressing Congress to act Tuesday.
"We have 11 million people here who we're not all going to deport."
Clear and present danger
Conservative Republicans have largely opposed Obama's immigration reform, declaring it an "amnesty" for people who broke the law by entering the country illegally.
"The president said 22 times he did not have the authority to take the very action on immigration he eventually did, so it is no surprise that at least one court has agreed," said Republican House Speaker John Boehner.
But advocates for immigration reform expressed confidence that Obama's actions would eventually be ruled legal, although there is concern the uncertainty may make undocumented migrants nervous to come forward.
"We are confident that the courts will ultimately side with the scores of legal experts, state leaders, city officials, and law enforcement leaders who say that these immigration initiatives are both in full compliance with law and deeply beneficial to our communities, society, and country," said Marielena Hincapie of the National Immigration Law Center.
Controversy over Obama's executive orders is also likely to burn on until the 2016 election.
The president has issued a slew of executive orders -- touching on North Korea sanctions, abortion, anti-gun-violence, the environment and a host of other issues.
Republicans, who since last year's mid-term elections have controlled both the House of Representatives and the Senate, accuse Obama of being authoritarian.
"President Obama's executive overreach on immigration poses a clear and present danger to our constitution," said House Judiciary Committee Chairman Bob Goodlatte.
"We cannot allow one man to nullify the law of the land with either a stroke of his pen or a phone call."
Historians point out that previous presidents have made extensive use of executive orders.
President Franklin Roosevelt used an executive order to establish internment camps during World War II and Abraham Lincoln used two to set out the Emancipation Proclamation, according to the National Constitution Center.