(This is not about the coronavirus pandemic, which I understand is a different issue, but about the six countries that had already been maintaining border controls since related to migration and terrorism since 2016.)
Could someone explain to me the legal basis of Germany, Austria, Denmark, Sweden, and Norway's extension of "temporary reintroduction of border control" declarations past the original 2-year deadline in November 2017? I'm trying to understand what the legal justification was for that, and I just keep getting more and more confused the more I read. Was the Commission's recommendation of September 2017 on extending the time frames adopted at some point? Or did they find some other loophole?
I have found some media references to them "switching to France's strategy" (which I don't understand well either) or switching from Article 29 provisions to Article 25 provisions. But when I read the Schengen Borders Code, I can't find anything in Article 25 that I can manage to interpret as allowing unlimited extensions.
I understand that there's an argument that what these five countries and France have been doing is indeed illegal, but I want to also understand what their own lawyers' argument would be for its legality.
Thanks in advance!