No problem with an identity card at all, after all we have passports and driving licences now.
The problem will come with all the data that someone somewhere will want to add to the card in the future, one we have the cards the addition of data to the card which we cannot seen will be the invasion of liberty. No doubt someone somewhere will suggest in 20 years time that all babies are "chiped" at birth to save us the bother of carrying the card around
wasn't there a film about this some years ago?