By its nature, a government produces absolutely nothing that could add to a nation’s GDP. Its sole duty is supposed to be the defense of the nation, from both external and internal threats. Its only source of money–which equates to power–is what it collects from its citizens. For those who would argue that the government employs millions and provides a paycheck for their families, consider this: every dollar the government puts into the economy via this method it has taken OUT OF the economy via some semblance of taxation.
Ultimately, private citizens working in unison with private companies provide 100% of a country’s profits, through the production of goods and the application of services. At its best, the government is a net neutral force with respect to a country’s economic success. At worst, it is a greedy and hungry beast beholden to none.