Capitalism is a system whereby wealth is in private hands. Communism is a system whereby wealth is in public hands. Capitalism is by definition corruption. Corruption is defined as putting public money into private hands. For example, if a politician receives a bribe by a company for a permit to mine in an area, then instead of the company paying taxes, i.e. paying the people, he is instead paying the individual politician who pockets the money. Hence bribery or graft is the privatisation of public money. It is a move to capitalism from communism.
Capitalism is a brilliant tool for increasing economic growth and increasing prosperity. What is most unfortunate about capitalism is that it flies in the face of what most people consider is fair, i.e. powerful and corrupt people control the economy and the workers are effectively slaves, some slaves more fortunate and more free than others. The optimal system therefore is a mixed economy, a capitalist economy with a communist redistributive taxation system that takes money from the rich to give to the poor. This is a good compromise. Most advanced economies already do this, e.g. America, Australia, Sweden, and Norway. However, poor countries cannot afford communism. They need capitalism to drive the economy. This is why poor countries are corrupt and why they need to be corrupt in order to develop.
Many developing economies nowadays, e.g. China, India, Russia, and Thailand have enjoyed significant economic growth, and most people agree that these countries are highly corrupt. This is because these countries have embraced capitalism and hence they have embraced corruption.
Karl Marx argued that countries undergo a natural evolution from feudalism to capitalism to socialism. Under capitalism, the rich use the workers for profit and pay workers a wage. Over time, workers accumulate wealth through their income and with wealth comes power. This allows workers as a whole to demand sick leave, public holidays, weekends off, and so forth. Over time, capitalism tends to evolve into socialism because exploitation of workers tends to give workers more power as workers accumulate wealth.
Many conservatives argue against socialist ideas, saying that socialist ideas hurt the economy. This is generally true. Take for example public holidays. The government deeming e.g. Christmas Day to be a public holiday is a socialist initiative that benefits the working class. It is a detriment to capitalists whose factories and other businesses have to be shut down for a day. In large factories that mass produce, one day of stoppage can mean millions of dollars in lost revenue. Socialist ideas hurt the economy. However, once an economy develops, if the government does not give workers their socialist demands, the alternative is worse. In a country that is already developed, the alternative to socialism is fascism. Fascism is defined as rule of the country by the powerful and for the powerful. Fascism will come about if there is an absence of communism. Without communism, the working class is impotent and the capitalist class control the government. If the capitalist class control the government, they will, through rational self-interest, implement policies that are anti-competitive and can lead to monopolistic inefficiencies. If we assume that humans are all greedy and are "rationally self-interested" then fascism is the direct by-product of capitalism. In a capitalist economy, those who have money and power will have an incentive to use government to eradicate competition, which means they will use government to eradicate rival capitalists. Politicians will, through rational self-interest, accept bribes or political donations from lobbyists, and the anti-competitive policies implemented will be detrimental for the economy. The only things standing in the way of fascism is communism, as the people as a whole can demand that government implement policies that benefit them. The force of democracy then leads to a situation in which politicians who want to please both voters and lobbyists, find a compromise. This compromise between the fascism promoted by capitalists and communism promoted by workers is normally called a "mixed economy" or even "socialism."