Doris Kearns Goodwin/headline needed

When Barack Obama delivers his inaugural address, he'll take part in a long-standing tradition.

Every president since George Washington has delivered the speech. The speeches have ranged from the shortest — 133 words at Washington's second inauguration in 1793 — to the longest — 8,445 words from William Henry Harrison in 1841.

We don't know how long Obama's speech will be Tuesday, but we turned to historian Doris Kearns Goodwin for some historical context. She starts by highlighting the significance of the tradition.