[Old Teufel Hunden]

"About 50 years later, we had the Mexican War in response to Mexican aggressive moves."

Actually, if you read the history of it, the Mexican American war was about "American Manifest Destiny" or what we might call today American Imperialism. Polk wanted the United States to go all the way to the coast. We went to war over the Republic of Texas applying to the United States for statehood and because Mexico would not sell us California. How is that agressive Mexican moves?

"50 years later we had the Spanish American war. After all was said and done, the problem was Spain moving in violation of the well known Monroe doctrine."

Spain had owned Cuba since 1492, the war had nothing to do with the Monroe Doctrine as Spain had already been there for a long time. If it was about the Monroe Doctrine, what was Commodore Dewey doing steaming into Manilla Bay uttering the famous line, "you may fire when ready Mr. Gridley"? If it was about the Monroe doctrine, why did we annex the Phillipines, Guam and Wake Island? The Spainish American war was mainly about Spains inherrent problem of settling the Cuban rebellion and the atrocities that were happening. That was one of the main reasons why the U.S.S. Maine sailed into Havana harbor and well, we know the rest of the story.

[DesertRhino]

“We went to war over the Republic of Texas applying to the United States for statehood and because Mexico would not sell us California. How is that agressive Mexican moves?”

Texas won independence 10 years earlier. Although defeated, Mexico never relinquished their former claim. Texas claimed to the Rio Grande as they applied for statehood.
Mexico claimed up to the Nueces.
The war established that Mexico did not own that strip and nailed down the limits of Mexican claims.