You have hit on an important point, the approaching demographic collapse of significant population groups in highly significant countries, for example Japan and across Europe.
In Europe's and Russia's case much of the replacement population will be fanatical moslems allowed free entry by leftist governments and paid to live and out-breed other groups by the welfare state in off-limits ghettos that do not allow assimilation into the new countries customs and standards.
Shariah will likely be the new norm across Europe over the coming years if not as the sole legal system, certainly as a parallel legal system.
Of course those who have enough money will be able to insulate themselves from the daily dangers of living in these shattered communities so it is of little concern to the leftist elite.
There are already reports of islamic hardliner youth wearing clothes bearing the slogan openly stating their goal that in 2050 they will take over the state aparatus due to superiority of numbers.
A democracy can be relatively easily perverted by a number of means, one of them is by deliberate change of the demographics of the country.
This deliberate change of voter demographics to increase the chances of election victory over time was a strategy employed by Blair in the UK to dilute the traditional English with new immigrants by an out-of control immigration policy.
It is potentially a long term strategy that the corrupt union front party (usually called labor but also aligned with so-called greenies) is attempting to employ here in Australia with their current out-of-control immigration policies.
By having continuing virtually uncontrolled immigration of people completely unfit to assume a productive position in your communities you ensure a growing pool of voters who will vote as a block for the party that promises to bribe the voters with the most social welfare services. This will inevitably be the union front (labor) party.