Twenty-two states prohibit direct corporate spending in state candidate elections, including eight that allow union donations:

States that prohibit corporate and union donations:

Alaska, Arizona, Colorado, Michigan, North Carolina, North Dakota, Ohio, Oklahoma, Pennsylvania, Rhode Island, South Dakota, Texas, Wisconsin and Wyoming.

States that prohibit corporate donations but allow union contributions:

Connecticut:

Unions can give up to $3,500 to a gubernatorial candidate, $1,000 to a state Senate candidate and $250 to a state House candidate per election

Iowa:Unions can make unlimited contributions

Kentucky:Unions can give up to $1,000 to a candidate per election

Massachusetts:Unions can give up to $500 to a candidate per calendar...