Complex sentence: Proponents of the Electoral College claim that it prevents a candidate from winning the presidency by simply winning in heavily populated urban areas, and pushes candidates to make a wider geographic appeal than they would if they simply had to win the national popular vote.
Split into simpler sentences: Proponents of the Electoral College claim the Electoral College prevents a candidate from winning the presidency by simply winning in heavily populated urban areas. This means that candidates must make a wider geographic appeal than they would if they simply had to win the national popular vote.