President Donald J. Trump’s wall along the southern border will cost at least $18 billion, per a Congressional source first reported by The Wall Street Journal. But, President Trump insists that Mexico will pay for the wall and that Democrats will agree to it.

According to The Wall Street Journal's source, the Department of Homeland Security has requested 316 miles of new fencing plus an additional 407 miles of reinforcing fencing to be built over the next decade, costing taxpayers $18 billion.

According to NBC News, Democrats are already condemning the plan. Sen. Dick Durbin of Illinois, the minority whip, called the request "outrageous."

"President Trump has said he may need a good government shutdown to get his wall. With this demand, he seems to be heading in that direction," Durbin said in a statement. He said that the administration was undercutting bipartisan efforts to help those protected by DACA with the $18 billion request and other immigration demands.

This figures comes as President Trump stated again today that he believes Mexico will pay for the wall. Trump was speaking to reporters from Camp David, where he is planning his 2018 agenda with Republican leaders this weekend.

“I believe Mexico will pay for the wall. I have a very good relationship with Mexico,” Mr. Trump told reporters.

He also added that construction of the border wall, a key tenant of his campaign, is absolutely necessary for any sort of deal on President Obama’s Deferred Action for Childhood Arrivals program. DACA has allowed thousands of illegal aliens brought into the country by their parents as children to stay in the United States, despite lack of proper citizenship.

It seems now that Trump is willing to compromise or grant amnesty to DACA recipients in exchange for the wall. “We want the wall,” Trump said. “The wall is going to happen, or we’re not going to have DACA.”

As noted by the Washington Post, for years Democrats have supported strong border security and even funding of a wall or fence along the border:

On the other side of the debate, wall proponents are perplexed why Democrats are voicing such vociferous opposition. In 2006, President George W. Bush signed into law the Secure Fence Act, a bill that authorized the construction of hundreds of miles of fencing along the border. That legislation was approved with broad bipartisan support, including, in the Senate, by such Democratic luminaries as Barack Obama (Ill.), Hillary Clinton (N.Y.), Joe Biden (Del.) and Charles E. Schumer (N.Y.), now the Senate minority leader. “Where I don’t understand the pushback is, in 2013 if everybody was for the 700 miles of double fencing, but now they’re not for it because Trump calls it a wall — to me that does not make sense,” said Brandon Judd, president of the National Border Patrol Council, the labor union for the border patrol agents. “Whether we call it a fence or call it a wall, it acts as the exact same thing — a physical barrier that makes it more difficult to enter the United States illegally. I don’t understand the whole fight over this.”

And In 1995, Bill Clinton’s State of the Union addressed the problems of illegal immigration, saying:

“All Americans, not only in the States most heavily affected but in every place in this country, are rightly disturbed by the large numbers of illegal aliens entering our country. The jobs they hold might otherwise be held by citizens or legal immigrants. The public service they use impose burdens on our taxpayers. That's why our administration has moved aggressively to secure our borders more by hiring a record number of new border guards, by deporting twice as many criminal aliens as ever before, by cracking down on illegal hiring, by barring welfare benefits to illegal aliens. In the budget I will present to you, we will try to do more to speed the deportation of illegal aliens who are arrested for crimes, to better identify illegal aliens in the workplace as recommended by the commission headed by former Congresswoman Barbara Jordan. We are a nation of immigrants. But we are also a nation of laws. It is wrong and ultimately self-defeating for a nation of immigrants to permit the kind of abuse of our immigration laws we have seen in recent years, and we must do more to stop it.”

It is still unclear how exactly the Trump administration plans on getting Mexico to pay for the wall.