I think Medicare is clearly a tax, it can't be an insurance program because there's no connection between 'premiums' and benefits.

Social security is nominally a government sponsored pension, but the payout ratios are weird, and it's compulsory, so I feel it's fair to call it a tax.

Same with at least the employee portion of compulsory unemployment insurance. Maybe that's generally an actuaraily sound program (I think the employer contributions may be), but in times of economic stress, payments increase and I don't think that's covered by premiums. I know there's a cap on benefits, but I'm not sure if there's a cap on contributions? Anyway, seems similar to Medicare and I'd call it a tax, too.

Although there is a "social security trust fund," it's an accounting fiction. Functionally the money you contribute goes to the general US treasury fund and payments to beneficiaries come from the general US treasury fund. It's really just a pay as you go entitlement.

>What you contribute is what you get out.

There's some correlation between in and out but the government isn't figuratively putting the money into a savings account for you.

It meets the tests of a tax: You can't opt out and the payee has a legal right to use the threat of violence against you in pursuit of payment.

> What you contribute is what you get out

That simply can’t be because what you get out is based on how long you live, which is a ‘known, unknown’