Credit Card Garnishment Withdrawn from checking account?

There must have been some kind of court order, or the bank wouldn't have let them have the money. Your wife should have been notified of any pending court action. But if she's moved and changed her name when you got married and didn't keep them informed of her whereabouts, it's very possible that any notification went to an old address and wasn't received by her, or that notification was done by publication in a newspaper - this would not let her off the hook.

If the account is joint, it can be taken for debts of both or of either of you.

I don't think that is legal but it depends on what the fine print said when you got the card. Many card companies changed rules after your sign up and the legality of that is questionable. Talk to an attorney.

Had to have been a judgement entered against your wife for a garnishment to have taken place. Check with her.

No legally...they would have to notify you of this and have court order paperwork to back it up. I would file and affidavit with the bank and see if they will reverse the charges.