Editor’s Note: This post was written by Michael Mills.

Very often, presidents can look back at the actions of their predecessors and learn a variety of things. This is no different for the presidency of James K. Polk, who was the 11th President and was in office from 1844-1848. During his presidency, Polk sparked the Mexican-American War to acquire California, secured American claims to Oregon, and oversaw the annexation of Texas. The Trump administration could surprisingly learn a lot of things from the experiences Polk had in office. One of the odder lessons the administration could take comes from the diary that Polk kept, detailing his presidency. He kept this thorough account in hopes that it would allow history to accurately and fairly judge him. In contrast, it did the opposite and portrayed Polk as a humorless and uncreative man. It has been hypothesized that this is the reason Polk has remained an obscure president in American history, despite his accomplishments. Similar parallels can be drawn to Trump’s Twitter account, which he often uses to defend himself from what he perceives to be unfair criticism. These tweets often lead to controversy and, based on the diary of James Polk, this could lead to a negative historical perception of his presidential character. Studies suggest that presidents with highly perceived character are often considered greater, even if this consideration is not warranted. For this reason, Trump’s negatively perceived tweets could result in a diminishment of his historical legacy; he may wish to take a lesson from Polk and evaluate his tweeting patterns.

The Trump administration could also learn a lesson about the “rally ’round the flag” effect from Polk’s presidency. This is the temporary popularity boost that is often seen after presidents take military action due to the wave of nationalism that follows. Polk witnessed this bounce after the outbreak of the Mexican-American War and used it as a pass for continued military action. However, as casualties mounted and the war got more expensive, public sentiment turned against it. Responses to Trump’s missile strikes in Syria were generally positive, and he did see a bounce in his approval ratings emulating this effect. Based on historical instances of the “rally ’round the flag” effect, it is important for the Trump administration to not view this as instant public support for additional military engagement in the region. Instead, the administration should use other factors, such as partisanship and goals of the campaign, to determine if public opinion will support prolonged involvement. Failure to do so could result in a loss of public support in elections, as was seen in the case with Polk and the Mexican-American War. Congressional elections after the war carried on indicated public disapproval, as Polk’s party lost the House in the midterm elections. This subsequent loss of public and congressional support as a result of prolonged military action could befall the Trump administration if they jump to action based on early public opinion bounces.

Information in this post about President Polk was taken from “James K. Polk: The American Presidents Series: The 11th President, 1845-1849” by John Seigenthaler.