I baulk at a political stance which is inherently based on another's work, instead of one's own efforts. Hence if the ruling party does achieve more, it is to the credit of the co-driver. And if not, the whip comes out. How easy it is to be an effective co-driver!
The injustice of such a strategy can easily demonstrated by translating it into our workplace. Imagine that your colleague decides that his sole duty is to ensure that you do your work. Whenever you do well, he hurriedly claims that it is because he has been watching you. Yet any lapse in performance is solely your fault. I would love to be in that colleague's situation. Surely no fair-minded person accept such a lop-sided distribution of responsibility!
Has this position been self-appointed to hide the genuine lack of alternative policy proposals and new ideas? If all the co-driver does is to look at the main driver, why do we need so many of them around?