How many war time presidents have failed to be relected?

Throughout U.S. history, there have been several wartime presidents who failed to be re-elected, notably including James Buchanan, who faced the Civil War's onset, and Lyndon B. Johnson, who chose not to run for re-election during the Vietnam War. Additionally, Herbert Hoover, during World War II, lost his re-election bid amid economic turmoil. Overall, the number of wartime presidents who have failed to secure a second term is relatively small.