What was that saying again? "Those who don't learn from history set our country's policy"?

"This war will be a cakewalk."
"They won't even fight back."
"They'll be glad we freed them from their oppressive government!"
"They'll greet us as liberators!"

Iraq, 2003?

Nope. Mexico, 1846:

The general assumption in the cabinet that Mexico would not fight the United States, or at worst could easily be defeated, was reflected in public opinion throughout the country. Although a few prominent individuals, including Senator Benton, warned that Mexico would fight valiantly to protect its lands, the general assumption was that a weak and degraded Mexico could offer no real resistance to the United States forces. It was even assumed at the beginning of the war that a Mexican population oppressed by the military, the clergy, and a corrupt government would welcome the invading armies. Throughout the conflict some argued that the United States was carrying freedom to the Mexicans, and that a true regeneration of the Mexicans was to take place. But it soon became apparent that most Americans believed that the Mexicans lacked the innate ability to benefit from the opportunity to be given them by liberating American armies.

...

The inhabitants of Mexico were expected to welcome the Saxons with open arms. A New York poet in May 1846 conjured up an image of Mexicans joyously shouting "The Saxons are coming, our freedom is nigh."