The Supreme Court case In re District of Columbia, No. 1., 1900 revolved around the issue of taxation in the District of Columbia (D.C.). The court had to decide whether Congress could impose a tax on real estate within D.C. without violating the Constitution's requirement for uniformity in taxation across all states. The plaintiff argued that since D.C was not a state, it should be exempt from such taxes. However, the Supreme Court ruled against this argument stating that while D.C is indeed not a state, it is still under federal jurisdiction and therefore subject to federal laws including those related to taxation. This ruling affirmed Congress' authority over fiscal matters within D.C and established precedent for future cases involving similar issues.

The dissenting opinion in the case of In re District of Columbia, No. 1., 1900 argued that the court majority had overstepped its jurisdiction by intervening in a matter that was primarily legislative rather than judicial. The dissenters contended that it was not within the purview of the courts to decide on matters related to taxation and public expenditure, which were under the exclusive domain of Congress as per constitutional provisions. They believed this decision set a dangerous precedent for future cases where courts could potentially interfere with legislative decisions based on subjective interpretations rather than clear legal principles or violations. Furthermore, they expressed concerns about potential conflicts arising from such interference and emphasized maintaining separation between different branches of government for effective functioning.