In some states, it is illegal to drive faster than 70 on the highway. In Texas, you can legally drive as fast as 85 on some highways. But the federal government no longer dictates how fast you’re allowed to drive in any state.

For about 20 years — from 1974 to 1994 — the feds did exactly that. It was called the National Maximum Speed Limit (NMSL) and informally known as Drive 55.

Everywhere.

Ostensibly, the NMSL was imposed as a fuel conservation measure but it was widely and rightly despised as an act of federal overreach that made what had been perfectly legal driving illegal “speeding,” via federal fiat.

The NMSL was finally repealed in the mid-’90s, returning to the states their rightful prerogative under the 10th Amendment to set speed limits within their borders — which they have ever since and without the sky or anything else falling.

Similarly — and also without the sky or anything else falling — a majority of states (46, to date) have decriminalized the possession/sale/use of small amounts of marijuana by adults for personal use.

Some allow — or rather, don’t criminally prosecute — medical marijuana as a treatment for chronic pain and other things, including glaucoma. Physicians and their patients are not treated as criminal “drug abusers.”

Others go a step further and allow recreational marijuana — on the same principle that states allow the recreational use of alcohol by adults — using the tax money generated to fund much needed infrastructure, such as road building and repair, new schools and so on.

There are also some states — such as Virginia — that have not decriminalized marijuana, whether for medical or recreational use.

While the laws regarding marijuana vary from state to state, the principle is the same: It’s not Washington’s business to micromanage the states.

That’s why there is a 10th Amendment, which leaves such matters up to the states.

For some time, this principle has been the de facto policy of the federal government, chiefly as the result of what’s known inside the Beltway as the Rohrabacher-Blumenaeur Amendment. It prohibits the Justice Department from using any funding authorized by Congress to prosecute individuals or businesses over the possession/use/sale of marijuana in states where this has been legalized — or at least, decriminalized.

The Rohrabacher-Blumenaeur Amendment was first passed in 2014 and has been re-approved each time a new federal budget has been approved.

But in 2016, Jeff Sessions — an old-time drug warrior — became the attorney general of the United States.

He is vociferously opposed to any decriminalization of marijuana, even for medical use and notwithstanding the proven efficacy of marijuana for the treatment of chronic pain, glaucoma and other serious ailments.

Sessions has made no secret of his desire to quash the Rohrabacher-Blumenaeur Amendment and the worry — among those who favor leaving this matter to the states — is that each year, there is a chance the Rohrabacher-Blumenaeur Amendment won’t be re-approved. If that ever happens, the attorney general (Sessions or otherwise) will then have the means at his disposal to resume prosecutions under the federal Controlled Substances Act — overruling the expressed will of the people in the 46 states that have decided to stop dealing with marijuana as a criminal matter.

To assure that does not happen, lawmakers on both sides of the aisle have joined together to make permanent the leaving of this matter to the individual states, as per the 10th Amendment and the principle of federalism it articulates. They include Republican Sen. Cory Gardner of Colorado and Democratic Sen. Elizabeth Warren of Massachusetts, who are co-sponsors of the Strengthening the Tenth Amendment Through Entrusting States Act.

The House version is co-sponsored by Reps. David Joyce, R-Ohio, and Earl Blumenaeur, D-Oregon, who co-sponsored the earlier Rohrabacher-Blumenaeur Amendment.

The legislation would go further than the stop-gap Rohrabacher-Blumenaeur Amendment by formally amending the federal Controlled Substances Act to disallow criminal prosecutions by the Justice Department in states that have legalized medical or recreational marijuana. Put another way, it would no longer matter whether the department has the financial resources to pursue criminal prosecutions under the Controlled Substances Act.

It would no longer have the legal authority to do so.

State laws would be respected, in keeping with the principle of federalism the 10th Amendment was specifically written to protect. People and businesses engaged in legal activities within their states would no longer have to fear federal swatting, a recurrent worry with Sessions champing at the bit and restrained only by lack of funding.

It’s ironic that Sessions — a Southerner and (ostensibly) a conservative Republican — is pursuing an agenda so contrary to the 10th Amendment, states rights — and the publicly expressed views of the president who appointed him. Donald Trump has repeatedly said he favors leaving this matter to the states.

The STATES Act would do exactly that — permanently.