Any American citizen traveling outside the United States is advised to carry a passport.
Passports serve as proof of nationality at border crossings and to United States consul officers in countries abroad. While entry into some countries such as Canada and the Bahamas is allowed passport-free, most countries require a passport with a legitimate visa stamped in it to enter. Generally, the passport agency is efficient allowing for both normal processing and expedited processing. Expedited processing allows for processing of your passport within five business days and is very reliable. If your date of departure is within five days and you have proof of that departure, you may be eligible for a Congressional expedite.