In 1933 FDR declared owning gold (inside the country) as being illegal.
I'd be very curious to see how a move like that would be taken today. Western populations are far more entitled and far less dutiful than that generation.
I'd say similar will happen again, not exactly the same as Gold is just not used now by most people as an asset. In India they would revolt as its been used for centuries without stop afaik, its feasible there as the government moves to formalise the national economy away from individual states towards a united tax policy.
What is most likely in the West is pension holders, who have received some tax benefits for that holding and are already restricted from access till a certain age. They will be forced to purchase government debt as their holdings in that pension, its already true that government run pension schemes do this as a counterparty to QE so hiding some of the effects that might occur otherwise.
However its possible all citizens in a nation could overnight see this action take place on their long term pension, its a fairly giant move but within the feasible reach of government and justifiable in a crisis even perhaps
