Donald Trump (right) is ahead of Joe Biden in swing state polling -- but these vacillating battlegrounds can turn on a dime
WASHINGTON — President Joe Biden and his predecessor Donald Trump clinched enough support last week to become the standard-bearers for their parties in November's presidential election.
Under the U.S. Constitution, each of the 50 states holds its own vote for the next commander-in-chief and candidates are awarded "electors" from each state according to its size.
With candidates needing 270 electors to win the White House, elections tend to be decided in the hotly-contested "swing states" with a history of alternating between Republican and Democratic candidates.
