The American Civil Liberties Union announced its intention to sue less than an hour after the White House released the text of Mr Trump's declaration that the "current situation at the southern border presents a border security and humanitarian crisis that threatens core national security interests and constitutes a national emergency".
But President Trump's declaration goes beyond previous emergencies in shifting money after Congress blocked his funding request for the wall, which will likely factor in legal challenges.
In his announcement, Trump explained his plans to divert funds from the Department of Defence military construction budget to building the wall.
And California's Attorney General Xavier Becerra promised to "definitely and imminently" launch a legal challenge to the emergency declaration, one of an expected flurry of suits against Trump's aggressive executive power move.
Several Republican senators are already indicating they could vote against Trump.
Wallace turned to Miller: "How does that justify a national emergency?"
Wallace asked Miller for examples of past presidents calling a national emergency to secure money they were denied previously by congress out of the 59 times a national has been declared previously.
The money in the spending bill Trump signed would finance just a quarter of the more than 200 miles (322 kilometers) of barrier he wanted this year.
On CNN, Senator Sherrod Brown of OH, a potential Democratic candidate for president in 2020, put it another way, referring to a familiar Trump promise from the campaign trail last time out. "A Democratic president can declare national emergencies as well", she warned.
Undaunted, Miller, who was the architect of Trump's effort to ban visitors to the United States from several predominantly Muslim countries, claimed voters would likely see "probably a couple hundred miles [of border wall built] ..." Chris Coons (D-Del.) said Congress should prevent the president from "getting around" the congressional process.
Beyond that, though, the law doesn't say what constitutes a national emergency or impose any other limits on the president.
Becerra said the emergency declaration was legally vulnerable.
A two-thirds vote by both the House and the Senate would be required to defeat a Trump veto.
The question of whether Trump's act was constitutional dominated the Sunday talk shows, administration figures and allies saying Trump was within his apportioned powers, Democrats saying otherwise.
Once your squads are set, 60 people drop down to a large map to look for gear and begin battling it out with other squads. McCoy went on to talk about why they went with a surprise and sudden launch instead of hyping up the game beforehand.
It was the first holiday season for the handheld system without a new Pokemon game, which was instead released on the Switch. Banners of Nintendo's new game console Switch are pictured at its experience venue in Tokyo, Japan January 13, 2017.
Two of three scheduled Air Force C-17 cargo planes that took off from Homestead Air Reserve Base in Florida had landed in Cucuta. He went on to say that Venezuela received 933 tons of medicines and medical supplies from Russia, China and Cuba on Thursday.
It promises to be a gripping occasion and the Wembley attendance will not be capped, meaning Spurs can hope for a huge crowd. Lloris calls for total concentration of the players and the presence of fans at Wembley to ensure victory.
The authorities were forced to open floodgates late Sunday, unleashing what they called "dangerous and high velocity flows". A silver lining to the deluge is that it has boosted drought-stricken farmers in western Queensland .
Sunderland Central MP Julie Elliott said "the downturn in the diesel market is what is being blamed" for the decision. The company said planned investment in the next-generation Juke and Qashqai, also announced in 2016, was unaffected.
There were echoes in Sarri's comment of something Jose Mourinho said a few days after he was sacked by Chelsea in December 2015. To lose 4-0 as Chelsea players is unacceptable. "Eden is 28, if he wants to leave, then he should do so".
Who is in Super Bowl LIII? Patriots 31, Rams 23 - My sixth sense tells me Tom Brady is going to be scary good. Patriots 35, Rams 27 - Marshall Faulk disrupts trophy presentation, says Patriots cheated again.
Russia's foreign minister said the USA withdrawal from the pivotal pact has further upset strategic stability. NATO allies have strongly backed Washington and urged Moscow to save the treaty by returning to compliance.
Dramatic rescue of baby underway in Durban
The baby, who was found with her umbilical cord intact, was believed to be between one and three days old. The community was also very supportive and helpful which was great'.
US Democrats unveil carbon-neutral 'Green New Deal'
Alexandria Ocasio-Cortez - denying her a coveted spot on a special panel on climate change and brushing off her Green New Deal". The proposals, which have come to be known as the Green New Deal, were crafted in conjunction with Senator Ed Markey of MA .
Real Madrid Believes in Treble
The French striker has 18 goals , six more than he had in all of last season. "We are expecting them at their best". The semi-final second leg will is scheduled for February 27, while a La Liga fixture follows soon after on March 2.
Trump ally Roger Stone charged with mendacity
Roger Stone , a confidant of President Trump, walks out of the federal courthouse last Friday in Fort Lauderdale, Fla. There is no allegation in the indictment that Stone actually communicated with Wikileaks.