Today Barack Obama becomes the first African American president of the United States. Standing before the U.S. Capitol building – which was built by black slaves – he will swear an oath (make a promise) that is given in the U.S. Constitution. It is this:
I do solemnly swear that I will faithfully execute the office of President of the United States, and will to the best of my ability, preserve, protect and defend the Constitution of the United States.
To do something solemnly means to do it seriously, to do it intentionally. To faithfully execute something means to do it exactly as one is supposed to do it. The office here means the job of president. The phrase to the best of my ability means as best as I can. The president promises to preserve (keep safe), protect, and defend the Constitution of the United States, which is the main legal document for our national government.
Most presidents, beginning with our first president, George Washington, add the words “so help me God” (may God help me) at the end of the oath, although it is not part of the official oath in the Constitution.
Congratulations to President Obama!