Making the Facts Fit the Case for War:
"In 1846 President James Polk announced that Mexican troops had fired on American soldiers on American soil, and he took the country to a war that eventually gained it California, New Mexico and Arizona. Was the disputed soil ours? Probably not. Did Polk distort the information he had? Almost certainly. He wanted the territory, and he needed a war to get it.

A first-term representative warned that if you 'allow the president to invade a neighboring nation whenever he shall deem it necessary to repel an invasion . . . you allow him to make war at pleasure.' For these words, Abraham Lincoln received the usual reward of political courage: he forfeited any chance of a return to Congress and was retired to private life for more than a decade. (Although he would do quite well after that.)

Our current dispute over the intelligence that led to the invasion of Iraq seems to be yet another illustration of this eternal principle: presidents and other decision makers usually get the intelligence they want. This doesn't mean that intelligence reports should be ignored, but that they must be viewed with skepticism.…"

http://www.nytimes.com/2004/02/08/opinion/08GOOD.html?pagewanted=all&position=