William O. Douglas,
United States v. White Bear Brewing Company…
“ The Court holds that a federal tax lien has priority over a statutory machanic's lien, even though the mechanic's lien was specific, prior in time, perfected in the sense that everything possible under state law had been done to make it choate, and was being enforced before the federal tax lien arose. The mechanic's lien arose out of a contract to furnish labor and materials for the improvement of the real estate. ”
