The resource-rich country was in a great power’s traditional sphere of influence. Unfortunately, its leadership was corrupt and inept, and its politics were chaotic at best. The standard of living fell significantly.
The great power responded to the instability by using every lever it had short of an open invasion to support its allies. The government managed to hang on, however, and stalemate was the result.
Is it Ukraine or Venezuela? Time will tell. Putin sent in his little green men; will Trump and Rubio do something similar? Don’t bet against it if the stalemate continues, as it probably will.