state instrumentality immunity

immunity from non-discriminatory taxation sought by a private person for his property or gains because he is engaged in operations under a government contract or lease cannot be supported by merely theoretical conceptions of interference with the functions of government. Regard must be had to substance and direct effects. And, where it merely appears that one operating under a government contract or lease is subjected to a tax with respect to his profits on the same basis as others who are engaged in similar businesses, there is no sufficient ground for holding that the effect upon the government is other than indirect and remote.