People interested in facts about Abraham Lincoln’s legacy of support for Mexico can see many key documents online as part of the Papers of Abraham Lincoln Digital Library that’s part of the Lincoln Presidential Library and Museum.
Perhaps the most significant documents for the Lincoln and Mexico Project pertain to Lincoln’s “Spot Resolutions” in the congress, which he used to allege that President Polk misled the congress about reasons for declaring war against Mexico in May of 1846. You can access the digital archives on this subject with this link: https://papersofabrahamlincoln.org/documents?fulltext=spot+resolutions&author=&recipient=&keyword=&type=&date=&earliest=&latest=&edition=true
The book Abraham Lincoln and Mexico: A History of Courage, Intrigue and Unlikely Friendships has been in the Lincoln presidential library since its publication. In it, historian Michael Hogan documents and discusses Lincoln’s reasons for challenging the president, and how the speech on the floor of the congress damaged Lincoln’s political career.
In early 2021, the new Center for Lincoln Studies in Springfield, Illinois, contacted Dr. Hogan to request an article to coincide with the official opening of the new Center. Here’s the full hyperlink to the article so you can share it with others. https://www.uis.edu/cfls/blog/lincoln-and-juarez-a-hope-for-renewal/?fbclid=IwAR1I3DE4Xp7RvbEAaoThTtrSRn-gjh_WcO_QwW2SbNlkvNhPAEh1pz1ReiM
In 2020, the National Park Service interviewed Dr. Hogan in a 15-minute podcast that the NPS created to help celebrate Hispanic Heritage Month. The podcast originated from Lincoln’s home in Springfield, Illinois, which is a historic site and part of the NPS. The discussion between the park ranger and Dr. Hogan focuses on the official visit by Mexican Ambassador Matias Romero to pay respects to the newly elected president in Springfield before Lincoln was inaugurated. Here’s the link: