In the post-American Revolution era, has the United States ever taken unilateral military action against another country besides during the Civil War?

  • 4
    I know this looks trivial to answer, but IMHO this is the kind of question it would be good to have an answer to here.
    – T.E.D.
    Sep 17, 2013 at 22:40
  • 2
    The question is very poorly researched, and could benefit from engaging with the theories of sovereignty and government that exist. Sep 17, 2013 at 23:35
  • Could even be considered asking for a list, which is specifically a type of question not to ask.
    – jwenting
    Sep 18, 2013 at 3:29
  • I agree with @T.E.D.. The op is not asking for a list. She/he is just asking if it has happened before. I think it is a very valid (though trivial) question.
    – Apoorv
    Sep 19, 2013 at 11:31

2 Answers 2


Yes, the USA has frankly engaged in unilateral military action so many times, it would be serious work just to count them all.

Just among declared wars, three of the five (a bare majority) were one-on-one wars that the USA declared first.

Among non-declared wars, this has been a common scenario. Presidents Reagan and Bush in the 1980s engaged in 3 of them that I can think of off the top of my head (Grenada, Panama, and the Libyan bombing).

Interestingly the official Marine hymn mentions two such military actions in the first line: The Mexican/American War, and the First Barbary War.

  • 2
    -1 for Grenada. It was not "unilateral military action" - it was undertaken on the request of legitimate government after a coup. As per Wikipedia: "Media outside the U.S. covered the invasion in a negative outlook despite the OAS request for intervention (on the request of the U.S. government), Soviet and Cuban presence on the island and the presence of American medical students at the True Blue Medical Facility." Same story as Clinton's Haiti invasion.
    – DVK
    Sep 18, 2013 at 13:12
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    @DVK I don't really care to reargue the politics of that invasion here. At the time the entire rest of the world (as well as a large portion of the USA) viewed it as a unilateral US military action. That's good enough for me.
    – T.E.D.
    Sep 18, 2013 at 13:45
  • @DVK Have you been reading this? openanthropology.files.wordpress.com/2013/10/grenadacia.pdf
    – James
    Jun 23, 2016 at 16:22
  • 1
    @T.E.D. that's patently false. Many countries in the region supported the invasion of Grenada both politically and militarily. "[T]he assault was staged by at least 500 United States marines and army rangers and 300 soldiers from Barbados, Jamaica, Antigua, St. Vincent's, St. Lucia, Dominica and St. Kitts- Nevis" (NYT)
    – suriv
    Aug 19, 2017 at 20:02

To name just a few of the better-known instances:

  1. Canada and Britain in 1812;
  2. Cuba1 in 1898;
  3. Assorted Indian Nations throughout the 19th century: Sioux, Apache, Cheyenne, etc.; and
  4. Grenada in 1983;


  1. The unilateral action was not against Spain, at least in a technical sense. Congress took unilateral action in support of Cuban independence, upon which Spain declared war on the U.S.
  • 2
    The Indian nations don't count as a "country", if we take the question at face value. But certainly in principle you are correct.
    – user2590
    Sep 17, 2013 at 22:51
  • 3
    @Vector - Debatable. However, ignoring those does not significanly alter the answer either.
    – T.E.D.
    Sep 17, 2013 at 23:05
  • 8
    +1 For mentioning Indian nations. Not counting them as countries/nations is racist "Flag Imperialism". youtube.com/watch?v=hYeFcSq7Mxg Sep 18, 2013 at 10:05
  • 3
    @Ryathal: That is what US history books claim; the accusation is disputed. Sep 18, 2013 at 21:38
  • 6
    Even if the US was provoked, it would still be unilateral. Unilateral just means we acted alone, without a coalition or allies.
    – Oldcat
    Jul 22, 2015 at 0:41

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