Legitimacy is under attack. Without legitimacy as a value, we have no argument against power. Without such an argument, there is no abuse of power, only use of power.
Putin and Trump have demonstrated how easily legitimacy is questioned, how precarious it is. I will say again what I have said before: it is not so much the means, but the ends, that count in questions of legitimacy. Government always employs disproportionate power, but it can be employed for the sake of further securing and enriching concentrated power or for the sake of creating a society more equal in the distribution of wealth and power.