U.S. President Donald Trump is expected to declare the situation on the border with Mexico a national emergency, in a move that would grant him vast powers and would likely be contested in Congress and in the courts.
Some members of Trump’s own Republican Party have expressed concerns about the national emergency, fearing both a degradation of the role of Congress and setting a precedent.
Democrats have long argued there is a humanitarian issue at the border but there is no national emergency.
The national emergency comes at the end of a process which saw Trump largely lose to Congress over funding for his proposed vast expansion of the border wall.
Trump pushed the federal government into the longest shutdown in history, ending last month after 35 days.
Trump announced his intention a day before funding for the government was again set to run out and as Congress was approving appropriations, but without cash for Trump’s wall.
The president has agreed to sign the funding bill and keep government open.
Trump is expected to take executive action to announce funding for the wall from alternative funds.
The entire process is being denounced by Democrats as a blatant attempt to bypass Congress, which is constitutionally viewed as having the power of the purse.
The appropriations bill has set aside 1.375 billion dollars for physical barriers on the border.
Trump campaigned on the border wall and pledged Mexico would pay for it.
He was also once a fierce critic of former president Barack Obama when he took executive action, evading Congress.