the erosion of national autonomy—and, with it, the state’s monopoly over violence, the power to enact binding laws, and other essential aspects of sovereignty. Sovereignty, in turn, is an obvious precondition for democracy (which you cannot have without a state). When the sovereign state erodes, democracy erodes.
He argues that consumerism is eroding sovereignty from within. I guess he means that people care more about personal economics than government.
He argues that globalization is eroding sovereignty from without. Corporations can cross borders more easily than government laws.
I can mourn the demise of a strong democratic nation-state if you convince me that the alternative is warlords and criminal gangs. But if the alternative is consumers shopping for what they want, including government services, then a strong democratic nation-state is not a good thing.