"In his own public statements, President Trump has made clear that his emergency declaration was triggered by his inability to secure funding for the border wall from Congress rather than an actual national emergency at the border," the California-led group of attorneys general wrote in their complaint.
That lawsuit, the most extensive yet filed, cites public statements and tweets from Trump dating to 2014, when he began advocating for a border wall on Twitter.
The "salient facts," the group wrote, including "the historic pattern of unauthorized immigrants committing crimes at substantially lower rates than native-born Americans," have not changed since Trump's inauguration in 2017.
Rather, the states allege that the president's inability to obtain funding from Congress is the reason for the national emergency declaration.
In addition to Trump's comments on Friday, the group of states cited the president's comments to reporters last month in which he said his "threshold" for declaring a national emergency was "if I can't make a deal with people that are unreasonable."
The president said on Friday that he was anticipating a number of legal challenges, and that he expected to ultimately be vindicated by the U.S. Supreme Court.
"Hopefully we will get a fair shake, and we will win in the Supreme Court, just like the ban," Trump said.
The justices upheld a version of the president's travel ban in June 2018 after it was blocked by lower courts. The ban was challenged on the grounds that it was motivated by hostility to Muslims. The top court's reasoning at the time could be good news for the president's national emergency declaration.
In the travel ban case, the state of Hawaii argued that the president's public statements and tweets demonstrated his intent to discriminate against Muslims. But the justices, ruling 5-4 in the president's favor, found that the tweets were not relevant to the case at hand, and instead relied only on the text of the ban itself.
"The issue before us is not whether to denounce the statements," Chief Justice John Roberts wrote in the opinion of the court upholding the president's order.
"It is instead the significance of those statements in reviewing a Presidential directive, neutral on its face, addressing a matter within the core of executive responsibility."