They raided the PERA fund by not making their obligated payments to the fund.  In years that the investment returns exceeded the 8% projection, the state reduced their contribution to the fund.  This created the shortfall when the return on investment didn't meet the 8% projection in other years.  The governor and the legislature diverted the contractual payments to PERA into other projects and created the insolvency with PERA.  This is not the fault of the state employees, it is the fault of the elected officials and their pet projects.