It's a very common practice for economies to peg their sovereign currency to a trading partner; there are on the order of 66 countries pegged to the US Dollar, and 20-odd pegged to the euro.

If a country wanted to move off of the euro, it would be pretty easy to create a sovereign currency pegged to the euro 1:1 by the countries central bank. Then in the future they could simply unpeg (or change the rate) if that became advantageous.

EU members aren’t fully sovereign. Some sovereignty is surrendered when joining the EU:

> "The EU law has primacy over national law and all decisions by the European Court of Justice, including orders for interim measures, are binding on member states’ authorities and national courts,” chief spokesperson Eric Mamer said.

https://abcnews.go.com/International/wireStory/eu-court-pola...

Also, a Eurozone country can’t abandon with Euro without leaving the EU.

The context here is comparing the the EU with the British Empire.

Statements like “The EU law has primacy over national law” make it pretty clear what it means to be a member of the EU.

Since you can exit, it's different.

Generally countries enter various nominally binding arrangements all the time, like ratifying UN treaties that are considered by courts to be part of national legislation etc. So "full sovereignty" in this sense is not so common.

(Also, EU law is drafted via a representational democracy system, so this use of power has an important quality of legitimacy that law handed down from the empire would lack)

The ability to leave doesn’t imply sovereignty.

There are non sovereign territories that have the right to become independent- but which are nonetheless non-sovereign.

"it would be pretty easy to create a sovereign currency pegged to the euro 1:1 by the countries central bank"

How will you protect the peg? If moving off the euro is taken as a sign of your weakness, defending the peg against the market shorting you will bleed your central bank dry.

IIRC, this was effectively what happened with the U.K. on Black Wednesday: https://en.wikipedia.org/wiki/Black_Wednesday

It’s easy to put a ceiling on your country’s currency trading range. The Swiss did this. Whenever the franc got too high their central bank would sell however much was necessary to stabilize the price.

And they stopped doing that because it wasn't maintainable.

Of course it was maintainable. They stopped doing it because the situation in the EZ more or less stabilized.

The Swiss central bank can always sell as many Francs as they want at any price that is below current bids and that’s always the case when defending an upside limit. They’re never going to run out of Francs to sell because they can issue without any technical limit.

Are you still a sovereign country when your currency is worth absolutely nothing and most internal transactions are done in a foreign currency? (case of several countries?)

"Having power over your own currency" is something not even the US has. Of course they're the hardest to push, but they don't have full control.

Were you forced to do that, or was that a sovereign choice? The answer lies there.

I am not even sure if we agree on the question, much less answer.

Some sovereign choices in history have proven to be "Hotel California"-style: joining a scheme was a sovereign choice, but leaving it not so much.

An obvious example is the US which does not let the constituent states secede, even though they joined the Union voluntarily. In a similar vein, Scotland joined the UK voluntarily (though in serious economic crisis), but it cannot just leave on its own when it decides to.

The process of joining the euro has been constructed as one-way only. There are no legal mechanisms to get rid of this obligation once you join. Euro is intended to last forever.

You're a sovereign country if you're able to sustain military control over your claimed territory. That's the only factor which really counts.

Of course you are. Unless somebody threatens to physically invade your country, your country can do whatever it wants. However there might obviously be trade/export/import sanctions etc.