President Trump has prioritized the construction of border barriers along the U.S.-Mexico border. Over the course of negotiations for FY2019 appropriations, the Administration asked Congress to appropriate $5.7 billion to the Department of Homeland Security (DHS) for that purpose. When Congress appropriated $1.375 billion to DHS for border fencing, the President announced that his Administration would fund the construction of border barriers by repurposing funds appropriated to the Department of Defense (DOD) and transferring funds from the Department of the Treasury. The Administration asserted that these funding transfers were authorized by a combination of the following federal laws: * National Emergencies Act (NEA). The NEA establishes a framework for the President to declare national emergencies. The NEA does not itself appropriate or authorize the transfer of funds, but the declaration of a national emergency triggers other statutory provisions that allow certain executive departments to repurpose existing appropriations.* 10 U.S.C. § 2808. Section 2808 becomes available upon the President's declaration of a national emergency under the NEA. This provision authorizes the Secretary of Defense to use unobligated military construction funds for the construction of otherwise unauthorized military construction projects.* Sections 8005 and 9002 of the 2019 DOD Appropriations Act. Sections 8005 and 9002 of the 2019 DOD Appropriations Act authorize the transfer of up to $6 billion appropriated in that act for "military functions" arising from "unforeseen military requirements." Funds may be transferred under these authorities only for "unforeseen military requirements" where the item for which funds will be transferred "has [not] been denied by the Congress."* 10 U.S.C. § 284. The 2019 DOD Appropriations Act also appropriated funds to a Drug Interdiction Account. Pursuant to 10 U.S.C. § 284, money in this fund may be spent by DOD in support of other agencies' counterdrug activities, including by constructing "roads and fencing . . . to block drug smuggling corridors across international borders of the United States." The Trump Administration proposed to use Sections 8005 and 9002 of the 2019 DOD Appropriations Act to transfer additional funds into the Drug Interdiction Account, which would then be used to construct border barriers.* 31 U.S.C. § 9705. This provision establishes a Treasury Forfeiture Fund (TFF) in the Department of the Treasury and authorizes the Secretary of the Treasury to make payments from unobligated sums in the TFF to federal, state, and local law enforcement agencies for various law enforcement purposes. Though a federal court in California initially entered an injunction prohibiting the Trump Administration from using the funds to initiate construction of border fencing, the U.S. Supreme Court ultimately stayed that injunction. The California federal district court's injunction would have prohibited the Administration from using Sections 8005 and 9002 to transfer funds for border barrier construction. The court did not rule on the lawfulness of the Administration's other proposed funding sources, though it did determine that waivers issued by DHS under Section 102 of the Illegal Immigration Reform and Immigrant Responsibility Act rendered NEPA inapplicable to the proposed border projects. But following the Supreme Court's stay of the district court's injunction, DOD was able to use funds transferred under Sections 8005 and 9002 for barrier construction purposes while litigation in the case continues. Other lawsuits challenging the Trump Administration's funding initiatives are ongoing in federal courts in the District of Columbia and Texas, though neither court has ruled on the merits of the Administration's initiatives. Meanwhile, both houses of Congress have continued to move through the annual appropriations process.