Passport Card...sufficient, legal ID?

Others may have more insight on this, but personally, I don't possess a US Passport card, just a passport book. And I've only been to Canada once, in March 2017, and haven't been to Mexico since the 1970's, so the book format has worked for my European travel, and I take it everywhere with me in my money belt.

I also have my Colorado Driver's licence, as a second form of legal I.D. However, I've managed to not get pulled over by the police lately, so other than having the passport when entering or leaving the USA and other countries at Border Control, and when showing my license at rental car counters, I haven't needed to present any I.D. The photocopy has never been needed, thankfully, to try to reestablish a lost passport. Bottom line, carry your actual passport, treat it like it's irreplaceable and don't lose it, and all is well.

Your passport along with the entry stamp is the only thing that proves you have entered the country legally. This is a perpetual discussion that will turn silly after about twenty responses. I personally do not see a problem without always carrying your passport. Others can dream up all kinds of situations. In the past 20+ years of travel in Europe we have had to show the passport unexpectedly three times. Each time I was damn glad I had it. Maybe a photocopy would have been OK, maybe a passport card, but no question about the passport. We showed it and exited quickly.

My position is -- better to have it and not need it, or need it and not have it? The probability of ever needing it is low but ???

I do not live near the border, so all I have is a passport book as we fly when we travel out of the US. I've never applied for a passport card.

Legal ID in Europe is national ID card (EU/EEA/Swiss citizens) and passport. Driving licences and passport photocopies are not legal IDs but may be accepted in certain situations depending on the country and local practice (Europe is not one homogenous lump, there are differences). Very few countries in Europe issue passport cards, there is no need for that - national ID cards serve as travel documents. I only know of Ireland and since the Irish passport card can be used in lieu of passport book for travel within the EU/EEA/Switzerland it does have legal status. I do not think US passport cards are legal in Europe in the same way as the Irish one is but if you are reluctant to carry your passport it is still better to have a passport card on you than nothing at all. Just be aware that it may not be accepted in all situations and you may be required to retrieve your passport from your hotel room. Still probably less hassle than having to get an emergency passport if you lose it.

Just carry your passport with you.

Your passport along with the entry stamp is the only thing that proves you have entered the country legally
I'm not sure that this is true, I think the passport is electronically detected and registered at the passport control desk in addition to the stamp.

Yes it is true. Even if the passport is registered at the passport control desk (this does not yet happen at all borders), this only proves the holder of passport 123456 is legal.
(a) You need to carry passport 123456 to prove you are that person.
b) A policeman will not have access to the database. What he will be looking for is a stamp on a passport, or an EU ID card or passport which has no time limit.

I agree with Frank's comment above:

This is a perpetual discussion that will turn silly after about twenty responses.

The fact remains that the only legal ID is a passport or an EU/EEA ID card. Driving Licences, foreign passport cards or anything else is simply NOT VALID. People may have been able to get away with them in certain circumstances, or private organisations may have accepted them, but the law is the law.

It seems to me that it might work better and look more official than a passport copy. Or, conversely, be held in your room and if you lose the passport, provide better information to the embassy for replacement. If a policemen asked for information to identify me, I really question whether he'd be looking for the stamp, as he's not immigration, and gray-haired mature women are more invisible than a threat, IMO. ;)

I know people don't hear this very well but a passport copy is of no value -- period. It is fraud. Anyone can take any picture and put it over your picture and make a copy. This is then a valid copy of a passport. About the only value to a copy is that it is useful if you need a replacement. True about looking for the stamp. The only time they looked for a stamp was at road block, and other two times they just wanted a passport -- NOW !! In the US police are not concerned about immigration but not sure if you can make the same assumption about all European police. Just carry the passport. Again, don't know what the big deal is about not carrying a passport.

https://community.ricksteves.com/travel-forum/italy/copies-of-passports-etc

A few years back I did a little research. I found that every former Warsaw Pact country plus Albania and Belgium required that you carry your passport with you at all times. A random check of Western European countries did not indicate the same requirement (except Belgium).

On my trip earlier this month I needed my passport for:

Purchasing a fishing license in Montenegro
Purchasing a 7 Day Travel Card in Budapest
Changing out dated paper currency in Budapest
Filling out paperwork for a tax refund on some expensive purchases in Budapest

Add to that showing it for boarding or boarding passes and upon arriving and departing countries (maybe 6 times)
Add to that Checking into hotels (4 times)

As a foreign visitor probably yes, but as a citizen that's not quite true. Poland was part of the Warsaw Pact and there is no law requiring carrying an ID card or passport. Every adult Pole has to have a national national ID card but does not have to carry it at all times. Most people do, however, it just sits in their wallet with all the other cards.

First, I was referring to U.S. Tourists and not Polish citizens or even EU Citizens. My bad for not being more specific.

Second, I did it "a few years back" and I don't know what if anything has changed.

If anyone wants to take the time to research and update. That would be great. When I couldn't find the answer on the State Department website or UK.gov site I wrote their embassy for the technically correct answer.