If an economy is bad it's assumed that it's because the leaders of the country do not set right economic policies in place.
In a democratic system, the government is voted into power by the majority, thus the government represents the people. It is the government that controls the human, material and financial resources. And from my observation, every nation has sufficient resources that can sustain its citizens and make them enjoy a good standard of living. The reason for poverty is the failure of the government to maximize and equally distribute the commonwealth of the nation.
Corruption has been identified as the main reason why most developing nations are backwards economically. In a corrupt nation, it is not just the government that is corrupt, the people are also involved in shady deals. But the simplest way to stop corruption is to vote in an incorruptible leader. The fish starts decaying from the head, and corrupt leaders institutionalise corruption.
If a nation is at war it's assumed that it's because of the decision of the leaders.
Some wars are not the fault of the government. Some nations have expansionist or conquest ideologies. They are just driven to invade to attack less powerful nations because they want to control their resources. In such a situation, a leader will have no option but to choose war.