Looking at the Indian subcontinent, I can only see Nepal, Bhutan, Maldives and SL integrate with India for economic reasons.
But if we look at history, Bhutan and Nepal managed to stay out of colonial realm and stayed independent though it was dependent on foreign powers for protection.
Looking at the western border, a split of Pakistan could result in creation of a Sindh nation. Would be assimilated in the Indian Union because of economics or use of force by India? As it is our national anthem is incomplete without that region in the Indian Union.
In Europe, could we see newer rivalries leading to wars and change of borders due to their downward economic status?
The US seems to be the safest place isolated by oceans on two sides and two large neighbors on two sides one of which is kind of an exptention of it and the other in too bad a shape to be a threat.