The men pleaded no contest in January to misdemeanor property damage. A fifth worker was found not guilty.
"This case had to be a public example of what can happen when you interfere with voters' rights," said Milwaukee County Circuit Judge Michael Brennan, who rejected prosecutors' recommendation of probation for the four men.
The Wisconsin state Republican Party had rented more than 100 vehicles to give rides to voters and poll monitors on Nov. 2, 2004. The cars were parked outside a Republican campaign office when the tires were punctured. The vandalism left the drivers scrambling for new vehicles.
Among those sentenced Wednesday were Sowande A. Omokunde, the son of Democratic lawmaker Gwen Moore, and Michael Pratt, the son of former acting Milwaukee Mayor Marvin Pratt.
"I love my son very much. I'm very proud of him," Moore said. "He's accepted responsibility."
Omokunde was sentenced to four months in jail; Pratt and Lewis Caldwell of Milwaukee were sentenced to six months; and Lavelle Mohammad of Milwaukee was sentenced to five months. All were granted work-release privileges.
Brennan also ordered them to pay a $1,000 fine each, in addition to the $5,317 in total restitution ordered earlier.
The four could have faced up to nine months in jail term and fines of $10,000.
Wisconsin's 10 electoral votes in the 2004 election ended up going to Democrat John Kerry.