On this point, countries should be in debt. If a country is not in debt it has more money it could be spending on its infrastructure/healthcare/education etc. (In addition taxation on marijuana alone wouldnt get the USA out of debt, although I dont know Trump's entire economic plan, I cant imagine taxing marijuana would have any noticeable effect).

A large part of the reason China became an economic superpower is that the government spent vast quantities of money to improve the infrastructure, particularly the country's rail network. Creating lots of jobs and improving China's ability to make things and to conduct business, both within itself and with other nations.