It's all or nothing winning electoral votes.
If you don't win a states votes then your opponent does.
If what you have to offer as a candidate only appeals to a few of the bigger states your opponent will win all the other states and beat you.
Thats why the electoral college is there. It keeps someone from appealing to a few high population centers winning with the popular vote and disregarding the rest of the country.
For example at the state level, in my state (New York) someone running for office only needs to appeal to the people living in New York City to be elected. The city is so large that its votes far outweigh the rest of the population of the state.
On the national level the electoral college prevents this from happening.
