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National Security

Our lawyers have firsthand experience in national security programs and policies at the most senior levels of the US government.


Mayer Brown's National Security practice advises clients on a wide spectrum of matters that involve sensitive national security issues. We have extensive experience working with the Department of Defense (DOD), as well as the Departments of State, the Treasury, Justice (DOJ), and Homeland Security (DHS); with federal law enforcement, intelligence, and military agencies such as the Federal Bureau of Investigation (FBI), Central Intelligence Agency (CIA), and National Security Agency (NSA); and with the increasing number of government entities that play a growing role in US national security today on issues ranging from energy to technology to trade. Our team assists companies as they engage with US government agencies and officials, navigate the global security environment, and grapple with laws, policies, and regulations aimed at addressing evolving threats and technologies. We represent clients supporting critical programs and missions in defense, homeland security, space, energy, and cybersecurity, as well as in matters involving sanctions and export controls, anti-corruption, immigration, and transactions subject to the Exon-Florio Amendment to the Defense Production Act of 1950.

Many of our lawyers have firsthand experience in national security programs and policies at the most senior levels of the US government, including the White House, DOD, DOJ, Department of the Treasury, Department of Commerce, FBI, NSA, Congress and US Attorneys’ offices around the country. Some of these positions include:

  • Former Commissioner on the bipartisan National Commission on Terrorist Attacks Upon the United States (“9/11 Commission”)
  • Former US Secretary of Commerce
  • Former US Ambassador to Romania
  • Former Deputy General Counsel, US Department of Defense
  • Former Counsel, US Senate Select Committee on Intelligence
  • Former Commissioner, The William H. Webster Commission on the Federal Bureau of Investigation, Counterterrorism Intelligence, and the Events at Fort Hood, Texas, on November 5, 2009
  • Former US Deputy Secretary of Commerce
  • Former General Counsel, US National Security Agency
  • Former Member of the Board of Directors, Overseas Private Investment Corporation
  • Two former General Counsels, US Department of Commerce
  • Current Chairman of the US-Iraq Business Dialogue
  • Former Special Assistant to the Director of the Federal Bureau of Investigation
  • Former General Counsel, US Immigration and Naturalization Service
  • Former Deputy Assistant to the President and Staff Secretary
  • Former Chief Counsel, US Senate Judiciary Committee, Subcommittee on Crime and Terrorism
  • Two former US Trade Representatives
  • Former Counsel, US Senate Committee on Homeland Security and Governmental Affairs
  • Former Deputy General Counsel, Department of Commerce
  • Former General Counsel, Commission on the Prevention of the Proliferation of Weapons of Mass Destruction and Terrorism
  • Former Representative of the Sixth Congressional District of Connecticut, US House of Representatives
  • Former Chair of the Section 1423 Panel (the Acquisition Advisory Panel) responsible for rewriting federal procurement laws

Several members of the practice currently maintain high-level security clearances in the US government, which allows Mayer Brown to represent clients in high-stakes matters that involve classified information. We are one of the few firms with litigators who have both the clearances and the experience required to handle such matters. We also have extensive experience with matters before the military and intelligence agencies within DOD.

National Security Policy, Legislation and Regulation
We are able to use sophisticated political experience and in-depth legal knowledge to advise clients on US defense and homeland security policy, legislation and regulation. We advise multinational businesses on national, state and local government issues, and we develop advanced legislative and regulatory strategies that address emerging issues across major industries. We have advised clients in need of multifaceted strategies to mitigate the political and economic risk inherent in conducting business with defense and security agencies and have engaged with US government entities seeking novel solutions to difficult challenges. We have represented clients and witnesses before congressional committee hearings and counseled clients on appropriate responses to congressional subpoenas and document requests.

Government Contracts
Our lawyers have the optimum balance of skills and seniority levels needed to address the legal and business challenges our clients face in conducting business with departments and agencies involved in national defense and security. These challenges include complying with disclosure obligations, responding to audits and investigations, conducting internal investigation, and litigating disputes, bid protests and false claims actions. We have represented clients in national security-related contracting matters involving DOD, DHS, the Intelligence Community and other US departments and agencies raising issues involving, for example, defense hardware and platforms, services support, space missions and research and development. We counsel clients on issues arising out of the US government’s efforts to fight terrorism militarily or with respect to cybersecurity and biodefense contracting. We assist clients on the supply chain implications of restrictive federal procurement rules and policies affecting trafficking in persons and counterfeit parts, as well as compliance with socioeconomic requirements. In addition, we assist with transactions involving foreign buyers of US companies or assets and compliance with the requirements of defense agencies, Exon-Florio, export controls and the FCPA. We are regularly involved in procurement policy and regulatory issues involving defense, aerospace, homeland security and cybersecurity.

Cybersecurity and Data Privacy
We advise clients on dynamic legal and policy issues involving cybersecurity and data privacy that implicate novel technology, national security, law enforcement and regulatory elements. Our experienced lawyers come from a range of disciplines, including regulatory, intellectual property, litigation, government, financial services regulation and enforcement, employment and business and technology sourcing. We help clients from all over the world comply with myriad data privacy and security regulatory obligations while minimizing risk and maximizing business opportunities in a constantly evolving threat environment. We provide strategic counsel in the following key areas: security incident preparation and breach response; litigation; strategic counseling and corporate governance; vendor and supply chain management, contracting and data transfers; regulatory and compliance; and policy and advocacy.

Sanctions and Export Controls
We advise clients around the world on cutting-edge issues involving US sanctions on Iran and Russia, as well as the many other restrictions on international trade and investment imposed for US national security and foreign policy reasons. We also assist clients with market access issues related to the easing of US sanctions and restrictions against Cuba. In this frequently changing field, we guide clients through the complex intersection of US policy, US sanctions laws and export controls, and attendant business risks and opportunities. Our clients span all industry sectors, and include banks, consulting firms and manufacturers in the United States and abroad.

Through our frequent contact with export control and sanctions regulators, we understand how agencies may interpret and enforce regulations in specific circumstances. We advise clients on US export and re-export restrictions, including compliance with the Export Administration Regulations (EAR) governing dual-use exports, the International Traffic in Arms Regulations (ITAR) governing the export of defense articles and services, and restrictions implemented by the Office of Foreign Assets Control (OFAC) on dealings with sanctioned countries and trading partners.

CFIUS and National Security Restrictions on Foreign Investment
We assist clients in the United States and other countries with navigating the US national security restrictions on foreign investments in the United States. Many of these investments are subject to review to determine whether they threaten to impair US national security. Our lawyers understand the full range of these restrictions and the nature of reviews conducted by the Committee on Foreign Investment in the United States (CFIUS) or as they arise under Exon-Florio.

We have advised clients on how to structure transactions to mitigate national security concerns while achieving business objectives, and we have helped clients establish compliance programs to govern classified facilities, cleared personnel, sensitive technologies and other elements of a US business that may pose security concerns. Several of our lawyers worked directly on significant CFIUS and Exon-Florio matters while serving in senior government positions at DOD and the Department of Commerce. Our lawyers have substantial experience working with defense agencies and companies that have defense contracts involved in acquisitions.

Cross-Border Investigations and Anti-Corruption
Our lawyers offer clients all-encompassing solutions to ensure compliance with an increasingly global framework of highly complex investigations and sophisticated regulators that are becoming more prevalent throughout the world. Our experience includes defending civil and criminal enforcement actions involving the extraterritorial application of US laws such as the FCPA, OFAC sanctions and related criminal prohibitions, the USA PATRIOT Act, money laundering prohibitions and politically exposed persons (PEP) regulations/guidance, the Racketeering Influenced and Corrupt Organizations Act (RICO), the Anti-Terrorism Act and the Alien Tort Claims Act. Working seamlessly with our colleagues in offices around the world, we advise on the complex, consequential and potentially global ramifications of cross-border investigations. The issues that we have confronted include data practices, state secrets, cultural differences in business, attorney-client privilege and labor and employment practices and protections, as well as the interplay of foreign countries’ laws with US domestic laws.

Immigration and Visa Issues
Our team manages not just visa and work permit authorizations, but the full gamut of global mobility issues impacted by US national security policies and regulations that our clients face on a daily basis. We assist clients (frequently on an enterprise-wide basis) with the necessary visa filings for their global offices. In complex cases, and in jurisdictions in which quotas or other local restrictions may apply, we provide customized counsel and identify the appropriate strategy for maximizing the chance of a successful submission. In some cases, this includes advising on the nature of the employment agreement or the company’s authorization to sponsor foreign workers in the United States. We are similarly accustomed to addressing complex personal challenges that may impact eligibility (e.g., prior visa denials, arrest records, serious medical issues and divorce or custody issues).

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