On This Day. 1787: the final draft of the Constitution was signed in Philadelphia, replacing the Articles of Confederation. It devised a system of checks and balances among three separate but co-equal branches of the federal government: executive, legislative and judicial /1 
One debate the Founding Fathers had concerned the representation of states: should big states and small states be represented equally—or by size? Their solution: both. States would be represented equally in the Senate—but proportionally in the House of Representatives
On This Day. 1817: Rebuilt after being burned by British troops in 1814, the White House once again became the president's home. James Monroe, president for six months, moved in for the first time home - and this is what it looked like (from south lawn) /1
After the White House was destroyed in 1814, James and Dolley Madison lived in nearby Octagon House (18th & NY Ave. NW) until his second term ended in March 1817. James and Elizabeth Monroe spent another six months there. Beautiful architecture (Photo/WWR)
On This Day. 1862: A nervous Abraham Lincoln waited for news on what remains the bloodiest single day in U.S. history—the Battle of Antietam. The clash near the Maryland town of Sharpsburg left 23,000 soldiers dead, wounded or missing (both sides) in 12 hours of savage fighting
Antietam is generally regarded as a strategic victory for the Union, ending the Confederate Army's first invasion of the North. It also gave President Lincoln the confidence to issue a preliminary Emancipation Proclamation just days later (we'll discuss this on Sept. 22)
You might be surprised to know that President Lincoln and his future killer John Wilkes Booth eyed each other at Ford's Theatre a year and half before the assassination. On This Day in 1863, Booth wrote to theatre owner John Ford, agreeing to appear in a play - which Lincoln saw
On This Day, 1964. Less than a year after her husband's assassination, Jacqueline Kennedy - suicidal and forced to flee Washington - was bombarded with interview requests from authors intent on writing about Dallas. She wrote to one, Jim Bishop, telling him to get lost
