Purges of voter lists
State efforts to purge voter rolls have led to disputes, notably in Florida. Before the 2000 election, Florida officials purged scores of thousands of registered voters on the grounds that they were convicted felons (and therefore ineligible to vote under Florida law). Many of those whose names were purged were "false positives" (not actually felons). (See Florida Central Voter File.) A post-election lawsuit brought by the NAACP, the People for the American Way Foundation, and other organizations resulted in a settlement in 2002 in which the state agreed to restore eligible voters to the rolls and take other steps to improve election procedures. 
The issue returned to prominence in 2004 when Florida announced another planned purge, again based on a list of felons. The state government initially attempted to keep the list secret. When a court ordered its release, it was found to contain mostly Democrats and a disproportionate number of racial minorities.  Faced with media documentation that the list included thousands of errors, the state abandoned the attempt to use it. Some of the voters improperly purged in 2000 had not been restored as of May 2004.
From Wikipedia not only democrats try to influence vote in unscrupulous ways.