What does “national law” mean in the United States? Is it the same as federal law?

In the United States, national law and federal law are the same thing.  National laws are enacted by Congress and signed into law by the President of the United States.

Because of  federalism, power is divided in the United States between the national government based in Washington, D.C. and state governments.  Both the state and national governments have the power to pass laws.  For example, New York State can pass a law that criminalizes certain types of conduct,  such as robbery, and the United States federal government can pass laws that would criminalize certain types of conduct, such as smuggling illegal goods into the country.  Here is a video on federalism:

Recognizing Federal and State Laws

There are some ways to recognize federal and state laws.

First, federal laws typically have a recognizable  popular name and a citation.  Popular name just means the name politicians give the law so people can recognize it.  For example, President Obama signed into law the Patient Protection and Affordable Care Act. But citation tells you where the law was published and that will always inform you whether the law is a federal law or not.  Federal laws are published in the United States Code, abbreviated as USC.

For example, let’s say you see a  law cited as:

18 USC § 2113

This tells you that the law is a federal law because it is in Title 18 of the United States Code, Section 2113.

If there is no “USC” in the title it is probably a state law.

For example, let’s say you see a law cited as:

NYPL § 160.00

As there is no USC in the citation it is not a federal law.  You also might be able to guess that the NY stands for “New York” and this happens to be a New York law.

A second way to distinguish federal and state laws is that Congress cannot enact any law that it wants.  Without going into too much detail here, federal laws will have some sort of connection to an issue that can affect the whole country.

If you see a law against littering, that is probably a state law.  But a law that criminalizes dumping waste into a river could be a federal law.  Of course sometimes laws overlap- – polluting a river might violate both state and federal law.  Likewise, robbing a bank could violate both federal and state laws.

Thanks to Omar for this question.