Photo by Mani Albrecht for U.S. CBP

The White House is taking steps to make good on Donald Trump’s campaign promise to build a borderwall between the U.S. and Mexico, requesting $18 billion over the next decade for construction costs from Congress, as reported by The Wall Street Journal last week. According to documents prepared by the Department of Homeland Security (DHS) on behalf of President Trump, this money would finance 316 miles of new barriers along the country’s Southwest border, as well as 407 miles of replacement or secondary fencing, according to an Associated Press article. If the project is completed, approximately half of the 2,000-mile border between the U.S. and Mexico would feature some sort of wall or barrier.

The president is demanding this funding in exchange for his signature on legislation that would protect Deferred Action for Childhood Arrivals (DACA) recipients—an Obama-era program giving young people brought to this country illegally a protected status—which he ended last year. The DHS delivered these requests to Congressional leaders, who are also in the middle of ongoing budget negotiations, potentially threatening a bipartisan comprise and thus presenting the risk a government shutdown as of Jan. 20.

“President Trump has said he may need a good government shutdown to get his wall,” said Senator Dick Durbin (IL-D) in an email to The New York Times on Friday afternoon. “With this demand, he seems to be heading in that direction.”

Trump’s request of $18 billion for the borderwall is just one in a list of demands made of lawmakers. The administration is seeking $33 billion in total border security spending for new technology, improved access roads, and thousands of additional Border Patrol agents.