Sen. Johnny Isakson, R-Ga., announced Wednesday he plans to retire at the end of 2019, citing health problems. J. Scott Applewhite/AP hide caption toggle caption J. Scott Applewhite/AP Politics Citing 'Health Challenges,' Republican Sen. Johnny Isakson To Retire At End Of Year August 28, 2019 In a statement, the senator said his Parkinson's disease was progressing. "I will not be able to do the job over the long term in the manner the citizens of Georgia deserve," Isakson said.