In the case of Millard v. Roberts in 1905, the U.S. Supreme Court ruled that Congress had constitutional authority to use public funds for local improvements in Washington D.C., even if they primarily benefited private interests. The dispute arose when a taxpayer, Edward S. Millard, sued John W. Roberts and other officials from the District of Columbia over their decision to allocate federal money towards relocating railroad tracks away from populated areas within the city center to more remote locations on its outskirts - an action which would benefit private rail companies but also improve safety and reduce congestion within D.C itself. Millard argued this was unconstitutional as it used public resources for private gain; however, Justice Oliver Wendell Holmes Jr., writing for a unanimous court, disagreed stating that such spending fell under Congress's unique role as both national legislature and local government for Washington D.C.. He further noted that while some individual businesses might profit more than others from these changes, overall benefits accrued to all residents by improving general welfare through enhanced urban planning.

In the dissenting opinion for Millard v. Roberts, Justice Harlan argued that Congress did not have the authority to use public funds for local improvements in Washington D.C., such as railroads, unless they were necessary for federal purposes. He contended that while it was within Congress's power to govern and maintain the District of Columbia, this did not extend to using federal money on projects solely intended for local benefit without a national interest or purpose. According to him, if there was no clear connection between an expenditure and a constitutional end or means of government function, then it should be considered unconstitutional. This case set a precedent regarding congressional spending powers which he believed could lead to misuse of public funds under the guise of serving 'general welfare'.