text: The Electoral College doesn't allow a candidate to win by gaining their electoral votes from one region. As stated in source 3, "no region has enough electoral votes to elect a president" meaning that if a candidate were to only campaign in a region that they knew would vot for them, then there is no possible way they would win. For example, in 2012 Mitt Romney was a favorite in the south so he had no incentive on campaigning heavily in other states because that he had won the south over completely. Not only did he not win a major electoral state, Florida, but he also didn't campaign in ohter states for which he gained no electoral votes. Even by some chance that they win, there is a very small chance of them being reelected because the regions that they didn't campaign in will feel disenfranchised and that will cause them not to vote for the president again. So if a candidate doesn't camapign in all regions that doesn't mean he won't win the election the first time, but he is likely to lose the reelection.