No, I am not saying to start shooting at the cops if they ask for this. I am saying to refuse, go to jail if they require it, then meet them in court, accusing them of wrongful arrest and violation of the 4th Amendment.
[Edit: This approach can get you in trouble that can take you years to get out of. Don't follow it if you aren't willing to face that.]
Voting out the people who are allowing this is very important.
We need to push for transparency in all aspects of elections, if someone says fraud, we need to be able to have evidence that no fraud occurred that is indisputable. Anyone should be able to examine the proof.
The hard part is to provide anonymity and transparency.
The harder part is getting people to agree to making transparency and accountability part of the process without one side or another providing a back door to the process.
The notion that you'll get good results by delegating all your political power to a representative for a period of years is asinine on its face, doubly so when their decision-making is subject to all sorts of perverse incentives, no matter how decent of a person they are. That seemed viable in a bygone era where the pace of change was glacial, to the extent that the America of 1776 would have been easily comprehensible to a Roman or Greek time traveler. In the early days of the American Republic, legal issues fo rhte average person did not change so much from before, except insofar as royal prerogative no longer existed. Many of the early landmark legal cases were about matters of state rather than relations between individuals and the state (obviously a generalization for the sake of brevity).
Over time the US (and other state) legal systems have inexorably grown in volume and complexity, for reasons that are still debated but ably summarized here: https://www.nature.com/articles/s41598-020-73623-x
This increase comes at a cognitive cost, both for individuals who enter or are caught up in the legal system, and for lawmakers and those who elect them. Endless patching with no practical opportunity for refactoring or rewriting in a situation that should be familiar to most HN readers and whose outcomes are quite predictable: either you freeze the code and it becomes increasingly brittle as the environment continues to change around it, or the code turns into an unmanageable mess that is in various aspects oppressive, corrupted, or exploitable by different actors, and social goods of coherence and predictability are inexorably eroded, a situation in which we arguably find ourselves at present.
Radicals of all political stripes (including myself) regard this as unsustainable but disagree on the values and mechanism that ought to replace it. Those who insist that everything is working fine and as the founders intended tend to be either successful collectors of political rents or naive optimists who have never seriously experienced or imagined life under other conditions, , like users of a software tool who have never felt any need to explore the preferences dialog or examine the paradigmatic foundation of the tools they've learned to use.
"If you were honest and actually thought about it, then of course you'd agree with me." So everybody who doesn't is either thoughtless or on the take. You are, at a minimum, not assuming good faith.
You can see the problems with the current system and still disagree with all the values and mechanisms that are proposed as replacements, thinking they are inadequate. That leaves you, by default, supporting the current system, not because you think it's the perfect system, but because you don't think any of the alternatives are better.
Thoughtless people are operating in good faith, but I consider them to be naive. I see no reason to assume good faith in all, that would be as foolish as assuming bad faith in all.
You can see the problems with the current system and still disagree with all the values and mechanisms that are proposed as replacements, thinking they are inadequate. That leaves you, by default, supporting the current system, not because you think it's the perfect system, but because you don't think any of the alternatives are better.
I presume by 'you' you mean you, not me. This isn't relevant to the first paragraph because I was critiquing 'people who insist that everything is working fine', not people who see and acknowledge problems.
So to restate your question: On what basis do the police think they can arrest you?
It's fair to point out that the police can arrest you unlawfully, and that's a real risk you run when saying "no" to them. But it's important to know that saying "no" to a request for your Twitter account name is legally very safe, and that the police would be way out over their skis arresting you for doing that.
Being detained for questioning is not a big deal, but being arrested is a very big deal, and it does not happen as casually as message boards think it does. If the police routinely arrest people without lawful cause, there are consequences (though they aren't the consequences any of us would hope there'd be).
There are more- and less- formal restrictions on how long they can detain you, but my mental model is just that they can detain you for basically any reason --- it is not my claim that there are magic words that can get the police to go away, or to stop asking you questions, and you might just have to put up with it until they get tired of you.
The next step, though, where they trundle you off to a police station for interrogation --- that's an arrest. It's a big deal. Actual cause is needed.
Let's run through a hypothetical. Routine traffic stop. Cop pulls out one of these cards and asks for your handles. You refuse, claim Miranda rights, or something similar. Cop says you, "match the description of a known suspect" (in a city as large as LA everyone matches a known suspect) and this is part of the ID process. "Of course, we can do a check using the computers at the station but you'll need to come with us until we confirm your ID ..."
Now, following through on that threat is an arrest, but under California law police have 48-hours to investigate before either charging you with a crime or releasing you. I doubt most officers would use the entire time, but letting someone stew for the afternoon in a drunk tank seems entirely within reason. During that time their car has been impounded and they're either missing work or missing time with their loved ones. Refusing to self identify could carry an effective fine in the hundreds of dollars, and that worries me.
If the argument is that the police will use this as a pretext to arrest people they want to arrest anyways, well, it's a dumb pretext. They have dozens of pretexts that aren't overtly unlawful; the idea that they're going to haul people in for an offense that they won't be able to articulate when they process you at the station (because it is not in fact a violation of any California statute) seems, to me, far-fetched.
It is problematic that they ask this question. I'm not lobbying for its inclusion. It's bad because people will, as has been pointed out all over the thread (including by my top comment) believe they have to answer. But the response to that problem should be to educate people not to answer the question, not to accept the victimizing framework of the article.
The police, by the way, cannot hold you for 48 hours while looking for something to charge you with. To arrest you, they need probable cause of a specific crime, which they'll need to provide when they book you. They can then charge you with other stuff they dream up while they hold you, but they need something to start with. Again: refusing to answer this question isn't "Obstruction of justice" (which isn't a California offense in the first place); the California "resisting" statutes generally require force or violence on your part, or your interference with their questioning of someone else.
The list isn't short.
Here, by the way, it's helpful to know that California doesn't even have an "obstruction of justice" statute (it has "Resisting arrest laws", which you can read more about to see that not giving your Twitter account up is not going to get you convicted of that).
The answer involves a lawyer, a lot of time, a lot of money, and low expectations.