The People do not elect the President.
The 538 persons in the Electoral College elect the President.

And what does the Electoral College base their decisions on? Who Knows? It might be things like:
1. Increasing their personal popularity for their personal re-election;
2. Compromises - "I'll scratch your back if you scratch mine;"
3. Bribes and other under-the-table dealings;
4. Fear that someone will send a hit-man against them or their family;
5. Some form of political advancement;
6. On rare occasions, what they think the people really want;
7. On even rarer occasions, what they know is best for the country;
8. Any number of other things that you, the reader, can guess;
9. Good-faith obedience to the SPIRIT of the Constitution.

Or any combination of the above.

See:
http://en.wikipedia.org/wiki/Electoral_College_%28United_States%29
http://www.realclearpolitics.com/epolls/maps/obama_vs_mccain/