Protecting the nation from international terrorists is primarily a federal job. Testing and credentialing people to drive is a local task. During the past several weeks, D.C. residents have been learning that, under federal law, the two overlap.

That’s the reason they now need to collect a bunch of identity documents and bring them to the Department of Motor Vehicles whenever their driver’s licenses expire. In many ways, the applicants are going back to square one to prove who they are, where they are and that it’s legal for them to be here.

This is not so much about making sure the right people are driving cars. It has much more to do with who is boarding airplanes. What D.C. drivers will go through when they renew licenses stems from the federal REAL ID Act of 2005, passed with the knowledge that many of the terrorists who brought down planes on Sept. 11, 2001, had been issued state driver’s licenses.

In the nine years since the act was passed, the effort to impose uniform security standards on the various approaches to issuing driver’s licenses has raised concerns among civil libertarians, privacy advocates and immigrant groups. But the ID law also has run into something at least as powerful: state bureaucracies that had their own histories of providing motor vehicle services.

Some states have refused to conform to the law. Many have been deemed in compliance. Some are still figuring out their own ways of conforming in consultation with the federal Department of Homeland Security.

The D.C. region illustrates the diverse responses to a law requiring uniformity.

The District Department of Motor Vehicles is now on track to revalidate their drivers as they come in with expiring licenses. The drivers must appear in person at a DMV office to supply proof of identity, address and Social Security number.

After this one-time-only appearance, they will be mailed a new style of driver’s license marked with a star in the upper right corner. The star indicates compliance with the REAL ID Act. This year and early next, the federal government is phasing in a requirement that only this compliant type of driver’s license can be accepted when a driver’s license is presented for identification at a secure federal facility or a nuclear power plant.

It may eventually be the only type of driver’s license accepted for boarding a commercial airliner, but that won’t apply before 2016.

Drivers who live in Maryland or Virginia who are aware of the new procedure for D.C. licenses may be wondering if they’ll get the same treatment as their licenses expire.

The answer is no. If I took my Maryland driver’s license in for renewal this week, I’d be subject to the usual vision screening, but I wouldn’t need to rummage for my birth certificate, or passport or proof of residence. And I’d walk out of with a license similar to the one I went in with — except for my somewhat older looking mug.

No star in the upper right.

And yet the Department of Homeland Security deemed Maryland compliant with the REAL ID Act back in 2012. For many years now, the Maryland Motor Vehicle Administration has been electronically verifying its drivers’ identifies, said spokesman Buel Young. The MVA worked through the long list of long list of security issues identified under the federal rules and the Homeland Security department accepted the state as compliant with the law, Young said.

Virginia is different. In fact, the General Assembly reacted to the REAL ID Act by passing its own bill in 2009 that prohibits the commonwealth from implementing any part of the REAL ID Act or other federal law that would compromise the economic privacy or biological data of any Virginian.

The Senate version of the bill was sponsored by then-state Sen. Ken Cuccinelli II (R) and signed into law by then-Gov. Timothy M. Kaine (D).

As of this spring, Virginia’s Department of Motor Vehicles is not compliant with the federal law. And the DMV has scheduled no changes in its licensing process.

But, said DMV spokeswoman Sunni Blevins Brown, “The Department of Homeland Security has acknowledged Virginia DMV’s significant progress enhancing the security and issuance process for credentials, and as a result, Virginia has been granted an extension until at least October.

“Virginians will not experience any difficulty in obtaining federal services or access to federal facilities with their Virginia credentials.”

It’s some of that e pluribus unum we’re famous for. The goal is the same, but for drivers, the procedures are looking a bit different.

“Virginia has one of the most secure licenses in the country,” Brown said of her non-compliant state.

What’s a driver to do? Follow the mailed instructions from your motor vehicle agency when renewal time approaches.

Dr. Gridlock also appears Thursday in Local Living. Comments and questions are welcome and may be used in a column, along with the writer’s name and home community. Write Dr. Gridlock at The Washington Post, 1150 15th St. NW, Washington, D.C. 20071, or e-mail .