The term "federal purposes" refers to any activities or programs that are carried out by the government at a national level, in accordance with its constitutional powers and responsibilities. This can include things like defense, foreign policy, trade, transportation, environmental protection, education, healthcare, and many other areas of public concern. The phrase is often used to describe activities or programs that are funded by the federal government, as it has a responsibility to ensure that these important matters are addressed for the benefit of all citizens.