About voter fraud - it exists but can only effect an extemely close election.

It only "works" on a district level.  It can effect a national campaign if that campaign needs a particular district to turn a state into an electoral victory.   It really has little effect on the larger, national vote count,  but,  again,  it is not the national vote that wins an election.  Elections are won or lost in district to district elections.  Example:  Win the vote in Pittsburgh and maybe you win Pennsylvania. 

Update:  You need to know that Democrats and Republicans are talking past each other in this discussion.  Fraud does occur in individual incidences and in certain districts  -  the GOP point.  It cannot substantially effect the national count, however  - the Democrat point. Lesson to be learned?  Let's stop trying to win the debate,  and admit that fraud can and does occur in the smaller-but-critical markets. 

Busing voters to a voting prescient is a form of voter fraud.  Busing only occurs in Democrat districts and is used as an opportunity to "school" the minority voter as to her intended vote.  THAT is fraudulent. 

Early voting can, also, be used in a fraudulent effort to sway a district election.  

But the case for "voter fraud" is most definitely found in the fact that all elections have precinct observers watching for fraud.  No potential fraud?  No need for the observers,  right?  

There are 1.7 million dead voters on our rolls.  There are 2.5 million folks registered in at least two states.  And there are 25  million voters with expired or useless registration information.  If you do not believe in "voter fraud,"  you are either too partisan walk up-right,  or you are part of the fraud issue.  

See you at the polls,  comrade.