The government imposes a tax through a three-step chain: the Constitution authorizes the taxing power, a legislature enacts a specific tax by statute, and an agency writes the rules and collects the money. At the federal level, Article I of the Constitution gives Congress the authority, a bill must pass both chambers and be signed by the President, and the Treasury Department and IRS translate the statute into enforceable regulations. States and localities follow the same pattern under their own constitutions and enabling laws. Nothing you owe is owed because an official says so; every dollar traces back to a specific grant of constitutional power exercised through a specific legislative act.
Where the Power to Tax Comes From
The federal taxing power lives in Article I, Section 8, Clause 1 of the Constitution, known as the Taxing and Spending Clause. It lets Congress “lay and collect Taxes, Duties, Imposts and Excises” to pay debts and provide for the common defense and general welfare.1Congress.gov. Constitution Annotated – Overview of Taxing Clause That clause is the engine behind every federal tax.
The original Constitution placed two limits on it. Duties and excises had to be geographically uniform, so Congress could not set one rate for one state and a different rate for another.2Congress.gov. Article I, Section 8, Clause 1 – General Welfare And Article I, Section 9 required any “direct tax” to be apportioned among the states by population, which made a federal income tax effectively impossible for over a century.3Constitution Annotated. Overview of Direct Taxes The 16th Amendment, ratified in 1913, removed that barrier for income taxes by authorizing Congress to tax incomes “from whatever source derived, without apportionment among the several States.”4National Archives. 16th Amendment to the U.S. Constitution – Federal Income Tax
Two other constitutional rules still bind Congress. The Export Clause flatly prohibits any federal tax on goods exported from a state.5Legal Information Institute. Prohibition on Taxes on Exports The Origination Clause requires that any bill for raising revenue start in the House of Representatives, putting the first move on the chamber closest to voters.6Constitution Annotated. Origination Clause and Revenue Bills
Who Can Tax What: Federal, State, and Local
Taxation is a concurrent power. The federal government and the states each have independent authority to impose taxes, and the lines between them matter.
Federal power is limited only by the constitutional constraints described above. State taxing power flows from each state’s inherent sovereignty, but it runs into two federal brakes. Under the Commerce Clause, a state tax on interstate activity survives only if the activity has a real connection to the state, the tax is fairly apportioned so the same dollar isn’t taxed in multiple states, it doesn’t discriminate against out-of-state businesses, and it reasonably relates to services the state provides. That is the four-part test the Supreme Court set in Complete Auto Transit v. Brady.7Congress.gov. Apportionment Prong of Complete Auto Test for Taxes on Interstate Commerce Separately, states cannot tax federal operations or instrumentalities, a doctrine that traces to McCulloch v. Maryland.8Justia. McCulloch v. Maryland, 17 U.S. 316
Local governments sit at the bottom. A city or county has no inherent taxing authority at all. Under Dillon’s Rule, a locality can only impose taxes the state has expressly granted or clearly implied the power to impose.9National League of Cities. Cities 101 – Delegation of Power Some states grant broader home rule authority, but even home rule cannot override state law. That is why property taxes, which states almost universally authorize, dominate local revenue.
How a Tax Bill Becomes Law
Because of the Origination Clause, a new federal tax starts as a revenue bill in the House of Representatives. The bill is referred to the House Committee on Ways and Means, the chief tax-writing committee in Congress.10United States Committee on Ways and Means. About the Committee on Ways and Means The committee holds hearings and marks up the text, setting the actual rates, thresholds, and structure. If the committee approves, the bill goes to the House floor.
A bill that passes the House moves to the Senate, where the Finance Committee runs its own process and often rewrites substantial pieces. When the two chambers pass different versions, a conference committee negotiates a single text that both chambers must then pass again. The final bill goes to the President, who can sign it or veto it; a veto can be overridden by a two-thirds vote in each chamber.11Constitution Annotated. Veto Power Only when the President signs, or Congress overrides, does the tax exist as law.
Why Sunset Dates Matter
Not every tax is permanent. Congress sometimes writes an expiration date, called a sunset, into the statute itself. The individual tax provisions of the Tax Cuts and Jobs Act of 2017, including the reduced rate brackets, the nearly doubled standard deduction, and the $10,000 cap on the state and local tax deduction, were all scheduled to expire after December 31, 2025.12Congress.gov. Tax Provisions in H.R. 1, the One Big Beautiful Bill Act
Congress addressed those expirations with the One Big Beautiful Bill Act, signed into law on July 4, 2025. The legislation made most of the TCJA individual changes permanent from 2026 onward, including the 10%, 12%, 22%, 24%, 32%, 35%, and 37% rate brackets, the increased standard deduction, and the 20% qualified business income deduction.13Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026, Including Amendments From the One Big Beautiful Bill The SALT deduction cap was raised to $40,400 for 2026 with annual increases through 2033, and the higher estate tax exemption was also made permanent.12Congress.gov. Tax Provisions in H.R. 1, the One Big Beautiful Bill Act The practical point for taxpayers is simple: a tax you pay today can change or disappear when its authorizing provision sunsets, so expiration dates in tax legislation deserve attention.
From Statute to Rules You Actually Follow
Congress writes tax law in broad terms. The Internal Revenue Code establishes what is taxable, but it rarely dictates every detail of how to calculate or report a specific item. Treasury and the IRS fill that gap through formal rulemaking.
Treasury regulations are the most authoritative tax guidance below the statute itself. They are produced under the Administrative Procedure Act: Treasury publishes a proposed regulation in the Federal Register, opens a public comment window, considers the comments received, and then issues a final regulation as a Treasury Decision.14Office of the Law Revision Counsel. 5 U.S. Code 553 – Rule Making Taxpayers can rely on final and temporary regulations, though temporary regulations expire after three years.15Congress.gov. Reliance on Treasury Department and IRS Tax Guidance Courts have struck down regulations where Treasury failed to follow proper notice-and-comment procedures or ignored substantive public objections.
Below regulations, the IRS issues revenue rulings, which apply tax law to a specific factual pattern. Revenue rulings carry less weight than regulations, but a taxpayer whose situation substantially matches the ruling’s facts can rely on it.15Congress.gov. Reliance on Treasury Department and IRS Tax Guidance The comment window on proposed regulations is often the only realistic chance for affected taxpayers to push back on how a tax will operate in practice before the rules harden.
How the Tax Reaches You
Once the law and the regulations exist, the mechanism of imposition is routine. The government defines what you owe, you report and pay it, and the agency checks your work. At the federal level, most individuals start with Form 1040, filed by the annual deadline.16Internal Revenue Service. About Form 1040, U.S. Individual Income Tax Return The IRS screens returns for discrepancies, conducts audits, and when it believes you owe more than you reported, can issue a notice of deficiency, levy bank accounts, or place liens on property.
Penalties for noncompliance stack quickly. The failure-to-file penalty runs 5% of the unpaid tax for each month or partial month a return is late, capped at 25%.17Internal Revenue Service. Failure to File Penalty The failure-to-pay penalty is a separate 0.5% per month on unpaid balances, also capped at 25%. That rate drops to 0.25% per month if you have filed on time and have an approved installment agreement, and climbs to 1% per month if you ignore a levy notice.18Internal Revenue Service. Failure to Pay Penalty Filing late with a balance due triggers both penalties at once.
How Long the IRS Has to Come After You
The assessment power is not open-ended. The general rule gives the IRS three years from the date a return was filed to assess additional tax.19Office of the Law Revision Counsel. 26 U.S. Code 6501 – Limitations on Assessment and Collection The window stretches to six years if you omitted more than 25% of your gross income.20Internal Revenue Service. Time IRS Can Assess Tax There is no time limit at all in two situations: you never filed a return, or you filed a fraudulent one. In those cases, the IRS can assess tax indefinitely.
If You Disagree With a Tax
You are not stuck with an IRS assessment you believe is wrong. Most disputes can be settled administratively through the IRS Independent Office of Appeals, which operates separately from the examination division that audited you. Conferences can be held in person, by phone, or in writing.21Internal Revenue Service. Appeals Process You generally have 30 days from the proposed adjustment letter to request an appeal. If the total at issue for each tax period is $25,000 or less, a brief written statement of your disagreement is enough. Larger amounts require a formal written protest laying out the facts, the legal basis for your position, and a signature under penalty of perjury.
When administrative appeals fail, the U.S. Tax Court is the only judicial forum where you can contest a tax assessment without paying it first. After the IRS issues a statutory notice of deficiency, sometimes called a “90-day letter,” you have 90 days to file a petition, or 150 days if the notice was sent to an address outside the United States.22Office of the Law Revision Counsel. 26 USC 6213 – Restrictions Applicable to Deficiencies; Petition to Tax Court The filing fee is $60, and fee waivers are available. Missing that deadline closes the Tax Court door entirely, which makes it one of the most consequential dates in the whole system. The IRS also recognizes a Taxpayer Bill of Rights that includes the right to pay no more than the correct amount of tax, to challenge the IRS’s position, and to appeal to an independent forum, and the Taxpayer Advocate Service exists to intervene when normal channels have stalled.23Internal Revenue Service. Taxpayer Bill of Rights