Even when this sort of thing is organized privately rather than by some rival polity, the ramifications tend to get out of hand: https://en.wikipedia.org/wiki/Archduke_Franz_Ferdinand_of_Au...

A more effective solution is to sponsor a resistance movement (whether militant or peaceful) and this has been done so often that it's been systematized in both military and civil terms by various imperial powers, but with (imho) increasingly mediocre outcomes and increasing risk of blowback.