In the electoral college system the population votes and however wins the majority in each state gets all the votes from that state this means that, there is always the danger that the winner of the popular vote will not win the presidency.
To put it into perspective imagine that you win by a landslide in one state with 10 electoral votes lets say a 70% - 30% vote difference; but than lose in 2 states with 5 and 6 votes respectively by a 49% - 51%.
This scenario means that you had more votes in total but are still losing the election 10-11.
