In the end, the USA has not invaded Mexico
Except it did.
As a result of the 1846-48 Mexican-American War, Mexico ceded to the U.S. present-day California, Texas, New Mexico, Utah, and Nevada, Arizona, and parts of Colorado, Oklahoma, Kansas, Nebraska and Wyoming.
What a great neighbor America is!
In a quote from Charles Sumner's "Objections to the Mexican-American War", he stated "Certainly Mexico might justly charge our citizens with disgraceful robbery."
Lincoln built his early political career, by deriding the Mexican-American war as the most despicable and shameful thing in the country's history.
By the way, the United States also tried to annex Canada. The only thing that put a tamper on it, was the British burning the White House down.
This means, America has attacked the only two neighbors with which it has a land border. Of course it didn't stop there, and invaded the rest of its "near abroad". Like the invasion of Cuba, on the false pretense of the Cubans sinking an American ship in Havana harbor.
Yes, America - a shining beacon of freedom.