George Bush was an excellent governor, not so much POTUS!! We ALL thought Christy was an excellent governor, has turned into a complete ass!! JEB was an excellent governor for FL. certainly not ready for POTUS!! Being a GREAT governor means nothing just ask Scott Walker who fought through union HELL, however completely flopped on the national stage!!
And then again, some Republican state governors went on to be great Presidents. Do I need to name them?