America has always distrusted its political leaders; we practically founded our nation on that principle. It's not likely to be something that can be fixed -- if it even should be -- by just electing the right person. Instead, what needs to happen is to elect leaders who will respect the rights of the people rather than advancing their own beliefs while disparaging the beliefs of others. That gives people confidence that their own lives are safe and won't be arbitrarily interfered with by government. That's a judgement not necessarily based on the system of government, but having a government that explicitly lacks the power to destroy its political opponents certainly helps a lot.
In his analysis, Roth found four factors that relate to the homicide rate in parts of the United States and western Europe throughout the past four centuries: the belief that one's government is stable and its justice and legal systems are unbiased and effective; a feeling of trust in government officials and a belief in their legitimacy; a sense of patriotism and solidarity with fellow citizens; and a belief that one's position is society is satisfactory and that one can command respect without resorting to violence.
When those feelings and beliefs are strong, homicide rates are generally low, regardless of the time or place, Roth said. But when people are unsure about their government leaders, don't feel connected to the rest of society, and feel they don't have opportunity to command respect in the community, homicide rates go up.