U.S. Customs and Border Protection released aerial footage shot on Oct. 17 of the eight prototype border walls near the U.S.-Mexico border "designed to deter illegal crossings." (US Customs and Border Protection Office of Public Affairs)

The Democrat-controlled Senate was nearing a make-or-break vote on a comprehensive immigration bill in June 2013 when a pair of Republican senators swooped in with an 11th-hour amendment aimed at clinching enough GOP support to avoid a filibuster.

A key provision: doubling the length of a new border “fence” between the United States and Mexico from 350 miles to 700 miles.

Democrats didn’t think such a barrier was necessary. Neither did the Obama White House. To them, the proposal seemed arbitrary — a random doubling of the size at the last minute for political purposes. In the end, though, all 54 Democrats in the Senate supported the provision in hopes of realizing a bigger goal — providing a path to citizenship for millions of undocumented immigrants.

This month, President Trump is ratcheting up demands that Congress include his border wall in a package to provide legal status for hundreds of thousands of immigrants brought to the country illegally as children. The administration is preparing to ask for $18 billion over a decade to renovate and build 700 miles of wall along the southwest border, according to a memo from the Department of Homeland Security.

“We want a wall,” Trump declared on Saturday after meeting with Republican leaders at Camp David in Maryland. “A wall must happen or we will not have” a deal.

At a Camp David news conference Jan. 6, President Trump walked through his priorities on immigration, including ending the practice of giving priority to immigrants' relatives and the lottery system. (The Washington Post)

Lawmakers face a March 5 deadline, set by Trump, after which work permits for the undocumented “dreamers” provided by former president Barack Obama under the Deferred Action for Childhood Arrivals (DACA) program will begin to expire at a rate of nearly 1,000 per day.

But the debate illustrates how the political stakes have shifted since Trump took office.

Democrats, under pressure from immigrant rights groups, have strenuously opposed including Trump’s wall in the negotiations. They call it a waste of taxpayer money, but they also have signaled that the political price for helping the president make good on his prime campaign promise is far too high.

Trump, through his anti-illegal-immigrant rhetoric and policies, including a travel ban aimed at Muslim-majority countries, has made the wall a metaphor to many Democrats of an administration whose crackdown on immigration they say has overtones of xenophobia or racism.

“The debate over a wall goes back decades. The notion of a wall is a giant symbol that is not based on analysis in any way of whether we should do something about the border,” said Cecilia Muñoz, a longtime immigrant rights advocate who served as Obama’s domestic policy adviser. “The fact is, having elevated the notion of a wall in his campaign the way he did, the president made it an even bigger symbol than it already was — and that makes it much harder to accomplish.”

In a letter to colleagues Friday, House Minority Leader Nancy Pelosi (D-Calif.) called the Trump administration’s request for wall funding “alarming” and said her caucus “must all speak out.”

On the other side of the debate, wall proponents are perplexed why Democrats are voicing such vociferous opposition.

A look at Trump’s border wall prototypes

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.”

In a statement, Schumer said, “We’d be glad to do comprehensive immigration reform, like the Senate bill from 2013, that has more of what both sides want, but that will take time. There is an immediate need to protect the DACA recipients, so the deal will be more narrow than that.”

It’s not just the wall that has scrambled the debate. Trump also is demanding changes to the nation’s legal immigration system, including curbing what the president calls “chain migration” — the practice of immigrants petitioning for extended family members to enter the country — and terminating a diversity visa lottery that provides 55,000 green cards to people from countries with low immigration rates to the United States.

The 2013 immigration bill approved by the Senate — with 14 Republicans joining the 54 Democrats — included provisions to end that lottery and to eliminate the ability of brothers and sisters of U.S. citizens to enter the country on family reunification visas. That bill also created a new category of “merit-based” visas in which prospective immigrants were awarded points for education levels and work expertise — another concept Trump has championed.

Democrats insist it is not fair to compare the 2013 debate to the current one. Five years ago, the negotiations were aimed at a far more sweeping comprehensive bill to fix an immigration system both parties agreed was broken. That legislation included changes to worker visas, cleared lengthy backlogs in legal immigration waiting lists, and offered a path to citizenship for all of the nation’s estimated 11 million undocumented immigrants.

This year, the debate centers on the fate of a far smaller group. Nearly 700,000 dreamers were enrolled in the DACA program, started by Obama in 2012, when Trump terminated it in September. Not all dreamers had applied for the program, however, and all told, depending on how the group is defined, there could be a total of more than 1.5 million dreamers in the country, according to experts.

Democrats have eyed a Jan. 19 deadline for lawmakers to approve a must-pass spending bill as leverage to forge a narrow deal for some portion or all of this group.

Trump signaled last fall that, although he was adamant that lawmakers beef up border security, funding for a wall did not have to be tied to the dreamer issue. In recent months, however, the president has emphasized that any DACA legislation “must secure the border with a wall,” as he reiterated Thursday.

Lawmakers remain uncertain about exactly what Trump is asking for. During the campaign, he called for a contiguous wall along 2,000 miles of the border, something even the Border Patrol union does not think is necessary.

After meeting with Trump at the White House on Thursday, Republican senators said such talk is misguided

Sen. Thom Tillis (R-N.C.) said that despite the president’s past campaign rhetoric, “he’s listened to border security” experts and now believes “there’s a need for walls and barriers in a number of places and the use of technology and personnel in others.”

Ultimately, Tillis said, Republicans are hoping for “a net increase of 600 miles of wall. That will be varying barriers based on where you are along the border, but that’s the long-term view.”

Democrats said privately that they need to hear directly from the White House just what Trump is proposing. Illegal crossings into the United States at the Mexican border have plummeted under Trump, making the need for a wall even less urgent in the mind of many lawmakers.

“If they’re really thinking that to give dreamers relief . . . that we’re going to give them significant monies towards a border wall,” Sen. Robert Menendez (D-N.J.) told reporters last month, “I can’t see that.”

Rep. Adriano Espaillat (D-N.Y.), whose Harlem-area district is home to approximately 2,700 constituents protected by DACA, called a wall a “nonstarter” in the dreamer negotiations.

Caving on a wall or on curbs to legal immigration in order to protect the dreamers is a wildly lopsided trade-off in favor of immigration hawks, Democrats said. Polls show that upward of 80 percent of the public favors a solution to allow dreamers to remain in the country, and some Republican lawmakers have said they support a deal — highlighting the complex politics for the GOP in a midterm-election year.

“This is a crisis they’ve created,” said Lorella Praeli, a former dreamer who became a U.S. citizen in 2015 and served as campaign adviser to Hillary Clinton. She now works as the ACLU’s director of immigration and campaigns.

Praeli said the Democratic strategy of supporting the border fence in 2013 in hopes that it would give the comprehensive immigration bill a better chance at becoming law was a mistake. The bill also would have spent $40 billion on border security, including nearly doubling the number of Border Patrol agents to 40,000 and adding high-tech surveillance equipment.

Although the Senate approved the bill by a vote of 68 to 32, it died in the Republican-controlled House where immigration hard-liners — opposed to granting “amnesty” to undocumented immigrants — forced then-Speaker John A. Boehner (Ohio) into shelving the legislation.

“They did the best they could under the context and politics at the time, but immigration politics have changed,” Praeli said. “There is a robust movement and accountability on Republicans and Democrats. Given the support on this issue and our constituency, we do not want to end up being in a situation where we say, ‘Sure, take what you need to give us a solution’ ” on the dreamers.