Can you name the Republican president who risked his career for Mexico?

At a time when much of border politics revolves around inflammatory rhetoric and divisive arguments, including talk of a "Hispanic invasion," it would be useful to reflect on an earlier period of U.S.-Mexico relations and a Republican president who had a quite different view of that country and its people than today's incumbent.

Few American students know that the 1846 invasion of Mexico by the U.S. deprived Mexico of almost half of its territory and resulted in the formation of several U.S. states, including California, New Mexico, Arizona, Utah and Nevada, as well as parts of Kansas, Oklahoma, Texas, Wyoming and Colorado. Few know that the treaty of Guadalupe Hidalgo, which officially ended the war in 1848, offered automatic citizenship to Mexicans in that captured territory, but the U.S. reneged on that provision.

When Abraham Lincoln was a first-term congressman from Illinois, he risked his political career by standing up in the House of Representatives and accusing President James Polk of invading Mexican territory without provocation and then misleading Congress to declare war on that country by claiming that "American blood was shed on American soil." In his remarks, Lincoln presented several "spot resolutions" asserting that any blood shed was on Mexican soil, and that the U.S. was the aggressor.

It did not go down well with Polk and his supporters. Lincoln was accused of giving aid and support to the enemy. Newspapers referred to him as "spotty Lincoln." Lincoln's Whig party would lose its majority in the House in 1848, and he would be defeated for the Senate race a few years later.