Democrats, led by new Speaker of the House of Representatives Nancy Pelosi, consider the wall to be immoral and have declined to approve the $5.6 billion Mr Trump wants as a part of the signature promise of his 2016 presidential campaign. Critics say the security risks are overblown and his administration is at least partly to blame for the humanitarian situation.
In a speech that will neither get the government running again nor change anyone's mind about anything, U.S. President Donald Trump will address the nation tonight in an attempt to make a prime-time case for his wall along the southern border-an effort most Americans have already said they don't support.
Schumer noted that Trump had promised to have Mexico pay for the wall. The objective of the address will be to promote his planned border wall between the United States and Mexico, characterize the issue of border security as a national security crisis and convince enough Americans to change their views on the subject that Trump can end the government shutdown by receiving border wall funding.
"Now that the television networks have made a decision to air the President's address, which if his past statements are any indication will be full of malice and misinformation, Democrats must immediately be given equal airtime", Pelosi and Schumer said in a joint statement.
Democrats have said they support increased border security measures such as additional US border agents and technology, but have rejected the administration's claims about the security risks at the border and have raised concerns that Trump will use his speech to present a false narrative.
Trump had spent days mulling declaring a state of emergency along the border that would have given him powers to bypass Congress, which has so far refused to fund the wall project, and draw funds from the military to build the border barrier.
Pence has also stated that Trump's address would lay out the facts of what the administration has called a humanitarian and security crisis at the southern border. The Mexican government has refused to provide such funds. There were almost 400,000 apprehensions at the border in the 2018 fiscal year, well down from the early 2000s when arrests regularly topped one million annually.
Trump explained in his speech the barrier was critical to security with thousands of Americans killed by those who had illegally entered the country. "It would very quickly pay for itself".
"The president was asked whether it [the national emergency option] is something he was considering, and he said it is something we are looking at...."
Senate Minority Leader Chuck Schumer also accused Mr Trump of trying to "govern by temper tantrum" and of manufacturing a crisis.
Mr Trump rattled off a number of grisly murders by illegal immigrants to justify the funding.
The shutdown, now into its 18th day, follows disagreement between the new Democrat-controlled House and the White House over budgeting several government departments whose funding has lapsed.