Colorado voters will soon decide whether people convicted of certain violent crimes should be held in prison longer before becoming eligible for parole. (Mike Sweeney, Special to The Colorado Sun)How did Proposition 128 get on the ballot? Republican lawmakers this year tried to pass a bill that would have had the same effect as Proposition 128. Supporters of the measure say it would boost public safety by keeping people convicted of violent crimes in prison longer. “I think common sense would say that people should be serving at least 85% of their sentence.”What’s the argument against Proposition 128?