My basic apportionment page addresses the argument that the income tax is unconstitutional based on Article 1, section 2 of the U.S. Constitution, which provides in part:

Two other excerpts from the original Constitution are also relevant:

As explained on the basic page, notwithstanding these provisions, it doesn't matter whether the income tax is "direct" or not, because of the Sixteenth Amendment to the Constitution, which provides:

So the rule of apportionment does not apply to income taxes.

Still, some people insist on arguing that the income tax is a "direct" tax. Therefore, they argue, it is invalid because of the constitutional prohibtion on direct, nonapportioned taxes.

In light of the 16th Amendment, the whole argument over whether income taxes are "direct" taxes is irrelevant. Under the 16th Amendment, Congress can lay and collect income taxes without regard to apportionment, period.

But even though it doesn't matter, let's imagine that, for some reason, we still want to know whether income taxes are "direct" taxes in the constitutional sense.

The answer is that the Supreme Court has long held that the income tax is not a "direct" tax, as that term is used in the Constitution. It is not subject to the requirement of apportionment provided in Article 1, §§ 2, 9. It is an "excise" or "duty," subject, presumably, to the rule of uniformity provided in Article 1, § 8.

That was the holding of the Supreme Court with regard to most kinds of income taxes even before the 16th Amendment, and the Court applied the holding to all income taxes after the 16th Amendment.

As early as 1880, the Supreme Court considered a case in which a citizen objected to paying income tax on the ground that the income tax was a "direct" tax subject to the rule of apportionment. The Supreme Court therefore needed to determine what constitutes a "direct" tax, as that term is used in the Constitution.

After a thorough examination of prior cases on the subject, the writings of constitutional framers such as Alexander Hamilton, the proceedings of the constitutional convention, and the analyses of distinguished constitutional commentators, the Court said:

Springer v. United States, 102 U.S. 586, 602 (1880). Thus, only capitation taxes and real property taxes are "direct" taxes. An income tax is an excise or duty. (A "capitation" tax is a fixed tax imposed on every person regardless of income or wealth.)

Simple, isn't it? Well, there was one complication. If property taxes are "direct" but income taxes are not direct, what about a tax on the income from property? For example, a tax on rents.

In Pollock v. Farmers’ Loan & Trust Co., 157 U.S. 429, on reh'g, 158 U.S. 601 (1895), the Supreme Court held that taxes on the income from property, like taxes on the property itself, are direct taxes that must be apportioned. The Court did not hold that taxes on other kinds of income (e.g., wages) would fall within this rule, but Pollock held the income tax unconstitutional insofar as it taxed the income from property without apportionment among the states according to the census.

The Pollock decision, however, gave rise to the 16th Amendment. That amendment, quoted above, overruled Pollock. In the subsequent case of Brushaber v. Union Pac. R. Co., 240 U.S. 1 (1916), the Supreme Court said that "the Amendment was drawn for the purpose of doing away for the future with the principle upon which the Pollock Case was decided".

With the rule of Pollock out of the way, Brushaber reaffirmed the prior rule that income taxes are excises or duties, not "direct" taxes subject to the rule of apportionment. In fact, Brushaber held that the point of the 16th Amendment was to make clear that income taxes are not to be considered "direct" taxes subject to the apportionment requirement. Ever since the 16th Amendment, the Supreme Court has recognized all income taxes, whether on income from property or on any other kind of income, as being outside the category of "direct" taxes.

So the bottom line is this:

First, it doesn't matter whether income taxes are "direct" taxes or not, because the 16th Amendment clearly states that Congress can impose income taxes without regard to apportionment.

But second, if, for some reason, you still want to know whether income taxes are "direct," the answer is that income taxes are not "direct" taxes in the constitutional sense. "Direct" taxes are only capitation taxes or real property taxes. The income tax is an "excise" or "duty."