Basically, in a war before the year 1900, but after the Revolutionary War, the US must enter a war, and lose it. Badly. Keep in mind, it must clearly be a loss, this can't be like the War of 1812(which I've heard was technically a US loss.) Additionally, it can't be the Civil War, it must be a foreign power. Finally, it must be a conflict where the US loses something significant, or must do something like pay reparations.
So, begin! I ask this because I'm wondering what kind of trouble the US can get into foreign policy wise before 1900.