FAS

Use of US Armed Forces Abroad, 1798-2019

07.19.19 | 1 min read | Text by Steven Aftergood

There are only nineteen years since 1798 when the U.S. did not have armed forces engaged in military operations abroad, according to an updated tally from the Congressional Research Service. See Instances of Use of United States Armed Forces Abroad, 1798-2019, updated July 17, 2019.

The most recent year in which U.S. military forces were not used in a foreign conflict was 1979, according to the CRS. The CRS account does not reflect covert action, disaster relief, or training activities involving U.S. forces abroad.

Though there have only been 11 formal declarations of war, there have been hundreds of military actions including “extended military engagements that might be considered undeclared wars.”

“These cases vary greatly in size of operation, legal authorization, and significance,” CRS said. “Some actions were of short duration, and some lasted a number of years. In some examples, a military officer acted without authorization; some actions were conducted solely under the President’s powers as Chief Executive or Commander in Chief; other instances were authorized by Congress in some fashion.”

*    *    *

Other noteworthy new publications from the Congressional Research Service include the following.

Critical Infrastructure: Emerging Trends and Policy Considerations for Congress, July 8, 2019

DOD’s Cloud Strategy and the JEDI Cloud Procurement, CRS In Focus, updated July 16, 2019

U.S. Strategy for Engagement in Central America: An Overview, CRS In Focus, updated July 17, 2019

Immigration: Alternatives to Detention (ATD) Programs, July 8, 2019

Beneficial Ownership Transparency in Corporate Formation, Shell Companies, Real Estate, and Financial Transactions, July 8, 2019

Hypersonic Weapons: Background and Issues for Congress, July 11, 2019

publications
See all publications
FAS
Article
Scaling Team Science is the Important Experiment We Need

X-Labs seek to expand on what FROs have shown is possible: the generation of foundational infrastructure for entire new fields of research science.

07.14.26 | 6 min read
read more
Government Capacity
Blog
An open letter to the new NYC PIT Crew

This is a tremendous opportunity to redefine what people expect from government, and in doing so, inspire cities across the country to raise their own ambitions. We are excited to see this initiative lead the way and look forward to cheering your success.

07.13.26 | 3 min read
read more
Government Capacity
Policy Memo
We Need a U.S. Permitting Corps: Executive and Legislative Recommendations

Despite significant political momentum behind reform efforts, limited attention has been paid to the federal workforce that will actually be responsible for interpreting and implementing new permitting regulations and better outcomes.

07.08.26 | 10 min read
read more
Environment
Press release
Amid Sweltering Weather, the Federation of American Scientists Releases Expert-Sourced “State and Local Heat Policy Agenda”

Nearly 150 organizations and government officials have endorsed the call to action and solutions for extreme heat, now public at HeatAgenda.US Washington, D.C. – July 7, 2026 – As millions of Americans continue to struggle to stay cool following one of the hottest Independence Day holidays on record, the Federation of American Scientists (FAS), one […]

07.07.26 | 3 min read
read more