A girl sits atop her father's back with a sign reading, "Trump is Over," at BLM Plaza near the White House in Washington on Nov. 6, 2020. (UPI/Kyodo)

WASHINGTON - U.S. President-elect Joe Biden has long been preparing to become the commander-in-chief of the world's most powerful country, building upon his vast experience on the global stage as a two-term vice president and longtime senator.