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"I will build a great, great wall
on our southern border, and
I will make Mexico pay for that wall.
Mark my words.”
Donald Trump

Great Wall of Mexico
US-Mexico Border Fence /

Secure Fence

Joe Biden promised he wouldn’t build “one more foot” of Donald Trump’s border wall. After his inauguration in January, Biden followed through, immediately halting construction on the wall and firing off a slew of executive orders to overturn Trump’s hardline immigration policies. As a senator, Biden voted in 2006 for the Secure Fence Act, which funded 650 miles of steel fencing and vehicle barriers along the border. The act passed both houses of Congress with bipartisan support, and was signed into law by George W. Bush that October. Biden said at the time that his vote did “not have anything to do with immigration,” but was aimed at stopping the flow of drugs across the border. Barack Obama and Hillary Clinton were also among the 26 Senate Democrats who backed the bill.

In an April 2021 meeting with Immigration and Customs Enforcement (ICE) officials, Homeland Security Secretary Alejandro Mayorkas said that his department may restart construction, in order to fill in some “gaps in the wall.” That’s according to a readout of the meeting seen by the Washington Times, a conservative-leaning news site. According to the report, Mayorkas told the ICE officials that while no new wall will be built, the Biden administration can still work on “gaps,” “gates,” and areas “where the wall has been completed but the technology has not been implemented.” US Border Patrol officials reportedly presented Mayorkas with the plan. These “gaps” are apparently hotspots for crossing attempts, according to recent reports.

The U.S. Defense Department asked Congress to reprogram more than $3.8 billion from FY2021 funding for the National Guard and weapons programs to pay for a wall on the border with Mexico, setting another possible confrontation with Democrats. Three years after arriving at the presidency, Donald Trump is keeping his central promise of building a wall on the southern border of the nation and heads his campaign for a second term with the same motto. Democratic aides said $1.5 billion would come from the National Guard, and the rest from funds for procurement, including the Lockheed Martin Corp F-35 fighter jet program, Lockheed C-130 transport aircraft, Boeing Co P-8 Poseidon maritime patrol aircraft, Bell Boeing V-22 Osprey tilt-rotor aircraft, and shipbuilding. Congressional Democrats called the request dangerous and misguided.

The president and his administration announced plans in September 2019 to build between 450 and 500 miles (725 and 800 kilometers) of wall along the nearly 2,000-mile (3,220-kilometer) border by the end of 2020. In some sections, a 30-foot-high wall will replace sections of Normandy barriers and post-n-beam fencing that by design only stop vehicles. Defense Department officials said 04 September 2019 that 127 military construction projects in both the United States and overseas will be deferred to free $3.6 billion for construction or augmentation of barriers along 175 miles of the southern US border.

President Donald Trump announced on 15 Feburary 2019 he would declare a national emergency to try to obtain funds for his promised US-Mexico border wall bypassing Congress, a move Democrats vowed to challenge as unconstitutional. "I'm going to be signing a national emergency," Trump said from the Rose Garden of the White House. "We have an invasion of drugs, invasion of gangs, invasion of people and it's unacceptable," he said. The president said he would sign the authorising paperwork later in the day in the Oval Office, freeing Trump to seek to redirect billions of dollars of federal funds. The emergency declaration enabled the activation of any of hundreds of dormant powers, which can permit the White House to declare martial law, suspend civil liberties, expand the military, seize property and restrict trade, communications and financial transactions.

This reprogramming decision was made after President Trump had repeatedly sought appropriations from Congress for the construction of a border barrier. Although Congress provided some funding for those purposes, it consistently refused to pass any measures that met the President’s desired funding level, creating a standoff that led to a 35-day partial government shutdown. The President signed the budget legislation that ended the shutdown, but he then declared a national emergency and pursued other means to get additional funding for border barrier construction beyond what Congress had appropriated.

Trump declared a National Emergency to use section 2808 of title 10, United States Code to bypass congressional intent and divert military construction funding from previously approved national security projects to fund a border wall. Congress chose not to fund this wall in the Consolidated Appropriations Act, 2019 (P.L. 116–6). There was bipartisan opposition to the action taken by the President, as both the House and Senate voted to disapprove the President’s emergency declaration. The House and Senate adopted a joint resolution terminating the President’s declaration of a national emergency pursuant to Congress’s authority under 50 U.S.C. § 1622(a)(1). H.R.J. Res. 46, 116th Cong. (2019). The President vetoed the joint resolution.

The requirements of section 8005 were not met because the need for which the funds were reprogrammed was not unforeseen, and it was an item for which funds were previously denied by Congress. The use of those funds violated constitutional requirements that the Executive Branch not spend money absent any appropriation from Congress. But on 27 July 2019 a Supreme Court ruling allowed the President to start taking funds from the military to build his ineffective border wall while litigation continued.

The administration asked for $1.6 billion for 2018 to build or replace 74 miles (120 kilometers) of barriers in Texas' Rio Grande Valley and San Diego and planned to request another $1.6 billion for 2019. A proposal by Customs and Border Protection called for spending $18 billion over 10 years to extend barriers to cover nearly half the border. The agency proposed 316 miles (505 kilometers) of additional barrier by September 2027, bringing total coverage to 970 miles (1,552 kilometers). It also sought 407 miles (651 kilometers) of replacement or secondary fencing.

The U.S. House of Representatives closed its summer session 28 July 2017 with a key legislative accomplishment that included a gift for President Donald Trump. House Republicans included a $1.6 billion request to build part of Trumps promised wall along the U.S.-Mexico border in a “mini-bus” package of bills. “We must be vigilant in protecting our homeland. That’s our priority. This legislation funds the most critical functions of government. It secures our borders by providing funding for a wall on our southern border,” House Speaker Paul Ryan said in a statement hailing the passage of border wall funding.

The project is months behind schedule. CBP officials said the winners would be announced in November 2017.

Donald Trump told reporters on Air Force One 13 July 2017 that his previous remark about placing solar panels on his proposed border wall with Mexico was no joke. "We have major companies looking at that," Trump said. "Look, there's no better place for solar than the Mexico border — the Southern border. And there is a very good chance we can do a solar wall, which would actually look good." Because of the presence of natural barriers, Trump said, the solar wall would need to span only 700 to 900 miles (1,125 to 1,450 kilometers) to be effective in halting illegal migration.

Trump told reporters on Air Force One that only 700 to 900 miles of wall may be needed. About 650 miles of the 2,000-mile long border already has some type of physical barrier. The remaining miles will be guarded by topography, the president said. “You have mountains. You have some rivers that are violent and vicious. You have some areas that are so far away that you don’t really have people crossing,” he said. He also opined that the wall should be see-through, ie, a fence, not a wall. Border patrol agents needed to be able to spot threats on the other side and avoid any “large sacks of drugs” thrown over the top.

Executive Order 13767 directed the Government to build a border wall with Mexico. The entire U.S.-Mexico border covers 3,200 kilometers, over a variety of terrain, from California, through Arizona and New Mexico and ending in southern Texas. More than 1,100 kilometers of that stretch already is fenced, but nowhere is the barrier as massive as the wall described in the new plan.

On March 17, 2017 the US Customs and Border Protection released two Requests for Proposal to award multiple contracts and initial task orders for the design and construction of wall prototypes. The Presidential Executive Order: Border Security and Immigration Enforcement Improvements, states that “the Secretary shall take steps to immediately plan, design and construct a physical wall along the southern border, using appropriate materials and technology to most effectively achieve complete operational control of the southern border.”

The US government planned to start awarding preliminary contracts by April 2017 for construction of a wall along the US-Mexico border, to fulfill one of President Donald Trump’s principal campaign promises. US Customs and Border Protection said it will accept "concept papers" for the wall’s design and choose the best ones by 20 March 2017. The agency will then ask vendors for construction cost estimates and, after reviewing their bids, begin granting contracts by mid-April — a remarkably quick schedule for a government construction project.

Trump said the wall will cost $12 billion, while Republican leaders in Congress have pegged its cost 20 percent higher than that. An internal Homeland Security report forecast the total cost could be as much as $21.6 billion.

The situation reached an impasse in December 2018. During negotiations with Congress over an appropriations bill to fund various parts of the federal government for the remainder of the fiscal year, the President announced his unequivocal position that “any measure that funds the government must include border security.” He declared that he would not sign any funding bill that did not allocate substantial funding for a physical barrier on the U.S.-Mexico border. But the President made clear that he still intended to build a border barrier, with or without funding from Congress.

The Border Wall: Symbol and Substance

The construction of a wall along the United States-Mexico border emerged as Trump's signature campaign promise in 2016 and remained a focal point throughout his first term. The concept for the proposed expansion of the border wall was developed in 2014 by Trump's campaign advisers as a talking point that would tie his business experience as a builder to his immigration policy proposals. During his campaign, Trump proposed a concrete wall between thirty and fifty feet high, covering one thousand miles of the nineteen hundred mile border, with the rest secured by natural barriers. He repeatedly promised that Mexico would pay for the construction, a claim that never materialized as American taxpayer funds ultimately financed the project.

During Trump's first term, the administration faced significant challenges in wall construction, including poor planning, problems acquiring private and public land, and funding shortages. The first Trump administration did not install a mile of wall in a previously unfenced part of the border in its first thirty months in office, instead focusing on projects replacing dilapidated fencing. By the time Trump left office in January 2021, approximately four hundred fifty two miles had been built according to Customs and Border Protection, though the vast majority of this construction involved replacing existing outdated or dilapidated barriers rather than building in previously unfenced areas. Analysis revealed that only about forty miles of new primary wall and thirty three miles of secondary wall were constructed in areas without previous barriers during his first term, while approximately three hundred sixty five miles replaced outdated fencing.

The physical effectiveness of the wall proved controversial throughout its construction and deployment. Maintenance records from Customs and Border Protection revealed that Mexican smugglers sawed through the wall multiple times per day using ordinary power tools. The agency recorded eight hundred ninety one breaches during fiscal 2019, nine hundred six during fiscal 2020, and one thousand four hundred seventy five during fiscal 2021. The government spent approximately eight hundred dollars per incident patching these holes, often leaving visible evidence of repairs. Border agents argued that smugglers tended to return to previously sawed sections because the bollards were weakened by initial cuts. Additionally, new dirt roads that had been used to access wall construction sites served as new access roads for smugglers, undermining some of the security benefits the wall was designed to provide.

The wall also created humanitarian concerns and safety hazards. Some individuals attempting to climb over the barrier with ladders or by hand fell as much as thirty feet, suffering severe injuries and in some cases fatal outcomes. From 2019 to 2021, the University of California at San Diego Medical Center recorded three hundred seventy five patients admitted due to falls from the border wall. The wall pushed migrants toward more dangerous crossing routes through remote areas, contributing to record numbers of migrant deaths. In fiscal year 2022, at least eight hundred fifty three migrants died crossing the border, breaking the previous year's record of five hundred forty six. The United Nations-affiliated International Organization for Migration declared the US-Mexico border the deadliest land crossing in the world.

Upon returning to office in January 2025, Trump immediately declared a national emergency at the southern border to unlock powers and funds for completing the wall. His second administration benefited from Congressional support, with Republicans securing approximately forty six point five billion dollars in the One Big Beautiful Bill passed in late spring 2025 for border security infrastructure. This represented a dramatic increase from the funding battles of his first term, including the longest government shutdown in American history that lasted thirty five days from December 2018 to January 2019 over Trump's demand for five point six billion dollars in wall funding.

The second Trump administration introduced the concept of a "smart wall" that incorporates advanced technology alongside physical barriers. This smart wall system includes steel bollard walls or waterborne barriers, roads, detection technology, cameras, and lighting. The administration planned to install two hundred thirty miles of smart wall complete with all elements, with an additional four hundred miles of the border receiving new technology. This technological infrastructure provides what officials call "domain awareness" through visual light spectrum monitoring, thermal imaging, radio frequency wave detection, seismic vibration sensors for tunnel detection, and radar systems. The integration of artificial intelligence and machine learning allows for enhanced analysis of images and information from border sensors, representing an evolution from the purely physical barrier approach of the first term.