If you’ve ever stared at an MBE question about a state trying to tax a federal agency and thought, “wait, can they even do that?” — you’re already thinking about federal immunity from state law, and you need to get this rule exactly right.

This is one of those Constitutional Law topics that looks simple on the surface but has enough nuance to cost you points if you’re not careful. Let’s break it down.

What Federal Immunity From State Law Actually Means

The core principle is this: state and local governments cannot directly tax or regulate the federal government or its instrumentalities. That’s it. That’s the rule.

It flows from the Supremacy Clause and was cemented in McCulloch v. Maryland back in 1819, when the Supreme Court struck down Maryland’s tax on the Second Bank of the United States. Chief Justice Marshall’s reasoning was blunt — the power to tax is the power to destroy, and states cannot be permitted to destroy federal institutions. That logic still governs MBE questions today.

Intergovernmental immunity is the formal name for this doctrine. It runs in two directions: federal immunity from state law (which this article covers) and state immunity from federal law (which is a separate Tenth Amendment question). Don’t mix them up. On the bar exam, confusing those two is an easy way to pick the wrong answer.

The Elements You Need to Know for the MBE

Here’s how to think about federal immunity from state law in a structured way:

1. Direct taxation or regulation of the federal government is invalid.

A state cannot impose a tax directly on a federal agency, a federal instrumentality, or federal property. Full stop. If a state tries to tax the IRS or charge the Department of Defense for operating a base, that’s unconstitutional.

2. Discrimination against the federal government is invalid.

If a state law singles out the federal government — or entities that deal with the federal government — for less favorable treatment than it gives comparable private entities, that law is invalid. A state cannot, for example, tax federal contractors at a higher rate than it taxes state contractors doing equivalent work.

3. Nondiscriminatory, generally applicable taxes are permissible.

Here’s where students trip up. A state can impose a nondiscriminatory, generally applicable tax on federal contractors or even federal employees — as long as it doesn’t discriminate against the federal government. If a state charges income tax on everyone who works within its borders, including federal employees, that’s fine. The tax applies generally. It doesn’t target the federal government.

This distinction — discriminatory versus nondiscriminatory — is where the MBE loves to test you.

The Mistake Most Students Make

The most common error is treating federal immunity as absolute. Students read “states can’t tax the federal government” and then apply it too broadly, concluding that any tax touching federal activity must be unconstitutional.

That’s wrong.

A nondiscriminatory state income tax applied to a federal employee’s wages is valid. A state sales tax applied to a private company that happens to sell office supplies to a federal agency is valid. What’s invalid is a tax or regulation that specifically targets the federal government or its instrumentalities, or that effectively discriminates against them.

Think about it this way: if you stripped the “federal” label off the entity and replaced it with a private company, would the state still apply the same tax or regulation? If yes, the law is probably fine. If the state is treating the federal connection as a reason to impose a special burden, that’s where you have an immunity problem.

MBE-Style Hypothetical: Spot the Issue

Try this one:

State X enacts a law imposing a 5% excise tax on all companies that provide construction services to the federal government within the state. Companies providing construction services to private clients or state agencies are not subject to the tax.

Is this constitutional?

No. This is a textbook violation of federal immunity from state law. The tax is not generally applicable — it specifically targets companies based on their relationship with the federal government. It discriminates against the federal government by imposing a burden on those who do business with it that isn’t imposed on those who do business with others. Under McCulloch and the intergovernmental immunity doctrine, this tax is invalid.

Now change the facts slightly:

State X imposes a 5% excise tax on all companies providing construction services within the state, regardless of who their client is.

Now it’s constitutional. The tax is nondiscriminatory and generally applicable. The fact that some of those companies happen to work for federal agencies doesn’t make the tax invalid.

Same rule. Different application. That’s the MBE testing you on whether you actually understand the doctrine, not just whether you memorized a phrase.

Federal Property and the Property Clause

One more angle worth knowing: Congress has plenary power over federal property under the Property Clause (Article IV, §3). This means Congress can authorize activities on federal land and preempt conflicting state law. When federal property is involved, states have even less room to regulate — not just because of intergovernmental immunity, but because Congress can expressly displace state authority over what happens on that land.

If an MBE question involves a state trying to regulate activity on a federal military base or national park, think about both intergovernmental immunity and the Property Clause. They can work together.

Don’t Confuse This With Preemption

Federal immunity from state law and preemption are related but distinct. Preemption is about Congress displacing state law in a particular field — it requires congressional action, express or implied. Intergovernmental immunity is a structural constitutional protection that exists regardless of whether Congress has acted. You don’t need a federal statute to invoke intergovernmental immunity. The Constitution itself provides the protection.

On the MBE, if a question is asking whether a state law is unconstitutional because it targets the federal government directly, you’re in intergovernmental immunity territory. If the question is asking whether a state law conflicts with a federal statute or occupies a field Congress has regulated, you’re in preemption territory. Read the call of the question carefully.

The FlashTables Connection

FlashTables is a set of professionally formatted two-column PDF rule tables covering all seven MBE subjects — 704 rules total, organized by the official NCBE Subject Matter Outline. The federal immunity from state law rule, including the critical distinction between discriminatory and nondiscriminatory taxes, is laid out clearly in the Constitutional Law tables alongside the full intergovernmental immunity doctrine. Whether you’re a law student building out your Con Law outline or a bar-taker drilling active recall in the final weeks before the exam, having these rules structured and scannable makes a real difference when you’re moving fast.

Key Takeaways: What to Memorize

Before you move on, lock these in:

Federal immunity from state law MBE questions are winnable. The rule is clean. The line between permissible and impermissible is the discrimination question. Once you’ve got that locked in, you’ll recognize these fact patterns instantly — and that’s exactly where you want to be on exam day.