Who was the last US president who did not start a war?

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    – T.E.D.
    Commented Nov 3, 2021 at 22:01

3 Answers 3


As noted in the comments, this depends on what you mean by "Starting a war".

  • Technically speaking, a war requires a formal declaration by Congress (though specific forms are subject to debate). As such, the last one started by the USA was in WW2, with declarations in 1941 (Japan/Germany/Italy) and 1942 (Romania and other Axys countries); which makes the answer to be Franklin Delano Roosevelt was the last one to start a congressionally-declared war, and every president since then did not.

  • More broadly speaking, if you count congressional authorization for the war, the last (and really only) 4 presidents since FDR who did not start a war were Lyndon B. Johnson, Richard M. Nixon, Gerald R. Ford, and Donald J Trump. So Trump is the answer to your question if you count wars that are not congressionally declared

The latter (Trump) conclusion is confirmed by various left wing newspaper fact checkers as of 2021 (Reuters, USA Today as random Google hits).

  • 9
    For people, killed by bombs, or their relatives, act of war was the war. It is not the law, but the history site. And the quesion is which president started, not which congress started.
    – Gangnus
    Commented Jan 28, 2012 at 23:09
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    @RonMaimon - en.wikipedia.org/wiki/Multinational_Force_in_Lebanon
    – DVK
    Commented Nov 3, 2012 at 20:44
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    @DVK Is that link correct? I'm not aware of the U.S. being involved in UNIFIL (beyond being a member and host of the UN obviously). Norway and France initially was it not?
    – lucideer
    Commented Jan 16, 2013 at 23:52
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    This answer is incorrect - Ford ordered military action against the Khmer Rouge - en.wikipedia.org/wiki/Mayag%C3%BCez_incident Commented Apr 2, 2013 at 17:15
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    Carter ordered the Iran Hostage Rescue mission, which was an attack on a country
    – Oldcat
    Commented Mar 6, 2014 at 18:08

The last time the US officially declared war against another nation was on December 8, 1941 - Japan. And that declaration was necessary, because Japan didn't declare ware on the US before starting the attack. Germany declared war on the US soon after. Franklin D. Roosevelt spearheaded that one, for those of you who really don't know your history.

However, officially declaring war appears to have gone out of style since then. If you want to define 'war' as a US president initiating military action against another nation, on a level that mandates congressional approval, that's a bit harder to define.

After Roosevelt, Truman authorized the US intervention in Korea, in conjunction with a UN resolution.

Eisenhower... inherited the Korean war and brought it to an end. He did keep US troops out of the Suez crisis, but he also sent troops into Lebanon in 1958, the Lebanon crisis. Technically, that wasn't an invasion, it was supporting an existing government. Eisenhower's administration was also involved in the 1953 Iran coup, although technically speaking, US forces weren't directly involved.

Kennedy kicked off the Vietnam war with the Gulf of Tonkin resolution, plus the unofficial backing of the Bay of Pigs invasion by rebels.

Johnson... didn't really initiate a fresh action, but he did escalate the US involvement in Vietnam considerably, from an advise and support with some troops role, into the US becoming the primary combat force.

Nixon authorized the incursion into Cambodia and Laos, although he wasn't attacking the Cambodian and Laotian forces, just N Vietnamese forces using eastern Cambodia and Laos.

Ford did authorize force against the Khmer Rouge (who were ruling Cambodia at the time) as a response to the Mayaguez incident.

Carter authorized the disastrous hostage rescue attempt against Iran, which technically was an armed invasion of a sovereign nation.

Reagan initiated the invasion of Grenada. His support of the contra rebels wasn't technically armed action by the US. He also sent 1200 Marines into Lebanon in 1983 as a peacekeeping force, leading to the bombing of the barracks at great loss of life, but technically, that wasn't an invasion, it was support of the existing Lebanon government.

GHW Bush authorized Gulf War 1.

Bill Clinton expanded the Somalia aid mission to include force, and then pulled the heavy weaponry out as a conciliatory gesture, leading to the Blackhawk Down incident.

GW Bush started the Afghanistan invasion, and then the Iraq invasion.

Obama initiated the Libya overthrow that directly involved US forces, and indirect involvement in Syria.

So it appears that the last president not to commit US troops to combat on a scale that requires congressional approval, was Eisenhower.

The last US president not to use the US military in a combat situation... Herbert Hoover, who left office in 1932.

  • IMO The CIA involved in the 1958 Iran were American "forces", so it sounds like the answer is Hoover. Commented Dec 1, 2017 at 2:46
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    None of these, except possibly Grenada (and the invasion of Panama, which you didn't mention) are examples of US Presidents STARTING wars. E.g. Roosevelt responded to Pearl Harbor, Carter tried to respond to the Iranian attack on US territory (embassies are considered territory of the country), GW Bush responded to the 9/11 attacks... In every case, the war was started by some other force, the US responded. Whether that response was appropriate or not is a different question.
    – jamesqf
    Commented Dec 2, 2017 at 6:36
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    Clinton is famous for bombing Serbia
    – Anixx
    Commented Mar 9, 2019 at 14:47
  • Committing combat troops is not the same thing as STARTING a war. Virtually all of your examples were responses to attacks on the US, so it was the other party which started the war.
    – jamesqf
    Commented Mar 15, 2021 at 17:22
  • I'm confused about why this answer does not address the Trump presidency. He has been in office for nearly a year at the time it was written.
    – bubbleking
    Commented May 23, 2023 at 20:02

If you mean start a declared war, then the last president to do that was Woodrow Wilson, in 1917. in 1941, the US declared war on Japan only to recognize that there already was a state of war. In 1917, Wilson started the US war against Germany, in the process stoking ethnic tensions in the US and the world that we are still paying the price for to this day

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