What if faithless elector vote for Romney despite Obama winning election?

Answer 1

This is theoretically possible, and at some points in history, so-called "faithless electors" did in fact break their own pledge to vote for a certain candidate, and instead voted for someone else; some sources say that this has happened with presidential electors more than 150 times over the centuries, but it did not affect the final outcome.

Such exceptions are rare, however, since it has become a custom that when a state awards its electoral votes to a presidential candidate, the expectation is the electors will cast their (largely symbolic) votes for that person; many electors are selected by their political party, so they understand how the procedure is supposed to work, and most go along with it. Interestingly, there are twenty-one states in which the electors are not obligated to do that. I enclose a link to a thorough list of state laws about electors, and which ones are not bound by anything other than custom or tradition.