Logical Fallacy Ad Hominem

One of the most widely used and famous logical fallacies is the ad hominem argument. What is the ad hominem argument? It is when person A tries to win the argument by attacking person B's personal life instead of attacking the points that person B made.

For example, 

Person A: "Person B's argument that the Yankees are better than the Red Sox is invalid because Person B lives in New York and would obviously be biased toward the Yankees." 

This argument style is extremely common in the political sphere with elections. An example of this argument is the swift boat ads of 2004 where Bush attacked Senator John Kerry (D) for Kerry's service to the country during the Vietnam War.  Bush said that since Kerry's service in the Vietnam War was not as strong as made out to be, then Kerry should not be President. These swift boat ads stayed away from the issues and attacked Kerry on defense making him seem unqualified to lead the country with foreign policy issues.