I think the problem is the government would not go to the trouble (nor get approval for) developing a solution that is not guaranteed to be used by anyone.

What you believe isn’t backed up by the long history of a national ID in the US. Your legal theory would have to explain, for example, why some States today (e.g. Washington) do not recognize or accept any Federal IDs, like passports, only State IDs. This is strictly in line with the Constitution, it is entirely permissible for States to reject Federal IDs for all legal purposes. What would compel a State to recognize any new Federal ID in the future if they already have the power to disregard Federal IDs in theory and practice?

A Social Security Number is not an ID expressly as a matter of law, because it can’t be legally. The many loopholes the Federal government tried to use to backdoor a national ID were shutdown by the Supreme Court repeatedly. The US can only have a mandatory national ID system if the individual States, in aggregate, decide to create one. Thus far, they have shown no interest. Real ID is not a unified ID because the Federal government cannot compel it.

As with most persistent problems, the “obvious” solutions are not being ignored because no one has cared or no one has tried but because there are fundamental technical reasons they don’t work.

The tenth amendment would be a good place to start. As others have out throughout this thread, the Constitution has a whitelist of powers allowed to the federal government. All other powers are outside it's purview.

Sure, but in the US, many many many more people have a state-issued ID than a federal one (a passport).

If a company needs to implement age verification, they're not going to limit their market to the set of US citizens with passports if the federal government were to offer an ID (passport) verification service. They're going to want state-run ID verification services, or, as in the case here, a private company contracted to do it for all ID types.

Then again, if the federal government (or my state government, even) offered an ID verification service directly, I would be more likely to use a product that offered it as an option, vs. one that only offered some private company's shoddy ID verification service.

But this feels vaguely analogous to the municipal broadband fights. Private ID verification companies would certainly lobby against states or the feds building their own ID verification services.

Indeed. We call them “passport holders”.

Not off-hand but it goes back to at least the early 20th century. There have been many attempts at a national ID system via technical loopholes but the courts have not looked kindly on them. It is the reason a Social Security Number is explicitly not to be used as an ID in law, so as to maintain its legality. It is the reason that every part of the Real ID Act that involves the Feds aggregating a centralized ID database from the States is strictly optional (and many States have opted to opt out of that). The Supreme Court has already ruled that Federal regulatory and taxation power cannot be used to induce States to comply, as that would be an end-run around Constitutional limits on Federal authority. Whether I like it or not doesn’t matter, I recognize that this is the reality.

As a heuristic, when something obvious and simple, like a national ID, has inexplicably never existed across every political administration, it is unlikely to be an oversight. This has been playing out for a very long time, it is unfortunate that most Americans are not familiar with the legal history.

It is similar to why people were surprised the government didn’t even try to enforce lockdowns during COVID anywhere in the US. Freedom of travel was thoroughly adjudicated across many cases by the Supreme Court covering almost every circumstance imaginable. Any prohibitions on freedom of movement are subject to the “strict scrutiny” standard, same as freedom of speech. Any politician attempting to do so would have invited instant wrath and injunctions from the judicial system, and their legal advisors knew it.

The Federal integration is optional, it cannot be compelled, and many States have opted to not implement it. The only thing the Real ID does is compel uniform standards for how States implement ID, it does not compel them to share their databases.

Good question! I think the short answer is because the Supreme Court has interpreted the constitution as having granted that power. It is not an open-and-shut case, however, and stems from the constitution's grant of power for Congress to control the Rule of Naturalization, and from the 14th amendment. A conservative reading of the constitution, however, might imply that Congress does not have the power to bar entry to foreign nationals.

> Article 1, § 8, clause 4, of the United States Constitution specifically grants Congress the power to establish a "uniform Rule of Naturalization."

http://hrlibrary.umn.edu/immigrationlaw/chapter2.html

> This passport function, recognized since 1835, is one of the privileges and immunities of American citizens protected by the Fourteenth Amendment.

https://www.yalelawjournal.org/forum/citizenship-passports-a...