From alternet.org:
“In some states, Republicans are threatening to conduct widespread vote challenges in heavily minority areas. In others, recent events suggest that poll workers may wrongly turn away voters. In still others, new laws passed or enforced by Republicans have erected hurdles to trip up the minority vote. And on Election Day itself, say advocates, Republicans may direct numerous tricks at Democratic districts in an effort to confuse or frighten voters.
Here’s a rundown of what’s happening in several swing states.”
For a different side to this debate, see Sughra Raza’s recent post on the ubiquitous nature of electoral fraud.