This is quite the day for pivotal events in American history:
1) 1787 - The US Constitution is adopted. Even now, two centuries later, people don't understand what the Second Amendment means.
2) 1862 - Just 75 years later, the Union nearly falls apart over a simple "We, The People" moment. Had the South won at Antietam, France and England would have recognized the Confederacy as a new nation. As it was, the battle allowed Lincoln to issue the Emancipation Proclamation just five days later, effectively bring the United States into the 19th Century. The South retarded us, yet again.
3) 2011 - Occupy Wall Street begins. Not a pivotal moment? Tell that to the folks in Europe who used it as a springboard to fight austerity measures, or the fact that it laid the groundwork to embarass the hell out of Mitt Romney and the Republicans this year. History will tell.