Ulysses S. Grant famously condemned the Mexican-American War as unjust, writing, "I was bitterly opposed to the measure, and to this day regard the war, which resulted, as one of the most unjust ever waged by a stronger against a weaker nation". He believed it was an unprincipled war intended to expand slave territory, acting as a direct precursor to the U.S. Civil War.
Ulysses S. Grant condemned the Mexican-American War