"The obligation to be enforced is the liability for the tax."

Section 280(a)(1) provides the United States with a new remedy for enforcing the existing 'liability, at law or in equity.' The quoted words are employed in the statute to describe the kind of liability to which the new remedy is to be applied and to define the extent of such liability. The obligation to be enforced is the liability for the tax. Russell v. United States, 278 U.S. 181, 186 , 49 S. Ct. 121; United States v. Updike, 281 U.S. 489, 493 , 494 S., 50 S. Ct. 367. The proceeding is one to collect the revenue. That Congress deemed the section necessary in order to make the tax-collecting system more effective is established, not only by the fact of enactment, but also by the reports of the committees. 4 [283 U.S. 589, 595] The right of the United States to collect its internal revenue by summary administrative proceedings has long been settled. 5 Where, as here, adequate opportunity is afforded for a later judicial determination of the legal rights, summary proceedings to secure prompt performance of ecun iary obligations to the government have been consistently sustained. Compare Cheatham v. United States, 92 U.S. 85 , 88-89; Springer v. United States, 102 U.S. 586 , 594; Hagar v. Reclamation District No. 108, 111 U.S. 701 , 708-709, 4 S. Ct. 663. Property rights must yield provisionally to governmental need. Thus, while protection of life and liberty from administrative action alleged to be illegal may be obtained promptly by the writ of habeas corpus, United States v. Woo Jan, 245 U.S. 552 , 38 S. Ct. 207; Ng Fung Ho v. White, 259 U.S. 276 , 42 S. Ct. 492, the statutory prohibition of any 'suit for the purpose of restraining the assessment or collection of any tax' postpones redress [283 U.S. 589, 596] for the alleged invasion of property rights if the exaction is made under color of their offices by revenue officers charged with the general authority to assess and collect the revenue. 6 Snyder v. Marks, 109 U.S. 189 , 3 S. Ct. 157; Dodge v. Osborn, 240 U.S. 118 , 36 S. Ct. 275; Graham v. Du Pont, 262 U.S. 234 , 43 S. Ct. 567. This prohibition of injunctive relief is applicable in the case of summary proceedings against a transferee. Act of May 29, 1928, c. 852, 604, 45 Stat. 791, 873 (26 USCA 2604). Proceedings more summary in character than that provided in section 280, and involving less directly the obligation of the taxpayer, were sustained in Murray's Lessee v. Hoboken Land & Improvement Co., 18 How. 272. It is urged that the decision in the Murray Case was based upon the peculiar relationship of a collector of revenue to his government. The underlying principle in that case was not such relation, but the need of the government promptly to secure its revenues.

[link to caselaw.lp.findlaw.com]

The government has no right to collect any tax for which there exists no liability statute (law). Note that this issue was never raised in Phillips v CIR. If you don't raise the point, you lose.

What law creates a liability for the income tax?