Initially, Section 7201 of the Internal Revenue Code would seem to create two criminal offenses. Section 7201 provides that a person commits tax evasion when he or she “willfully attempts in any manner  to evade or defeat any tax . . . or  [its] payment.” However, case law has interpreted the statute to create only one offense, but which may be committed by two means.
That is, initially, Section 7201 would seem, by its terms, to create two criminal offenses. First, there is the offense for willfully attempting to evade or defeat a tax assessment. This would include, for example, filing a false income tax return that “low balls” or omits your income. It also includes claiming deductions that you are not entitled to. Why is this a crime? The answer is because it falsely lowers your “taxable income,” which is the figure used to compute your tax liability. Thus, it rises to the level of “attempting to evade or defeat tax” because it is evading the correct amount that is supposed to be assessed against you.
Second, Section 7201 creates an offense for willfully attempting to evade or defeat the payment of a tax. Typically, this offense arises after the IRS has asserted you owe a tax, and the taxpayer actively conceals money or assets from the government in an attempt to avoid paying his or her tax liability.
However, even though a close reading may suggest that Section 7201 creates two offenses, in reality, it creates only one offense but two methods of committing it. The Ninth Circuit reaffirmed this holding in 1991 in United States v. Mal, 942 F. 2d 682 (9th Cir. 1991). There, the Ninth Circuit, which is binding precedent for those living in California, held “that § 7201 charges only the single crime of tax evasion, and that an individual violates the statute either by evading the assessment or the payment of taxes.” Id at 688. Furthermore, even the IRS’s own Tax Crimes Handbook explains that “[t]hese two offenses share the same basic elements necessary to prove a violation of I.R.C. § 7201.” http://www.irs.gov/pub/irs-utl/tax_crimes_handbook.pdf