The assumption of this question is that all western government is corrupt, when in actuality the only place on the planet where institutions are honest and generally free from corruption are in the west.
In the west if you ask a policeman for help, he will actually help you. That is a staggering fact compared to many other places in the world where the police are state sanctioned thugs that can do as they like with you.
Likewise if you are accused of a crime you are considered to be innocent unless proven guilty beyond a shadow of a doubt. All law is accusatory meaning that if someone accuses you of something, it’s up to them to prove their claims. You are not guilty until proven innocent which is often the case in religious dictatorships or theocracies around the world.
Also, literally anyone can run for office in the west, this is important because most people have a common morality, the people at the bottom of the socio-economic pyramid are often more moral than those at the top who have allowed themselves to be corrupted by outside influences in their pursuit of power. This means that most people in politics are there for the right reasons and collectively they can outvote and tone down the influence of really bad people who are there for the wrong reasons!
Finally all government institutions in the west are secular, meaning that they are not under the direct influence of the church. The government looks after everyday life and the church looks after your spiritual life including the afterlife and that’s the way that it should be. A religious system that is also political is already corrupt and of no service to the people, a fact that we collectively realised during the enlightenment of the 16th and later centuries to the point that we’ve separated church from state, in a development that transformed our societies as we know it, making it the most fairest and equal in all of human history.
Whilst it’s not perfect and is always in need of improvement, it’s the best that the world has ever seen and should be celebrated at every opportunity. Life in the west is an incredible gift that we should all be thankful for, because it has been hard won, the maintenance of such a civilisation is constant and is the greatest gift that you can leave your children.