Thanks, Izzy!

Okay, here's how I see it. We can actually use both
a or
the for this context; it makes no difference whatsoever here.
I'll tell you, though, that I would prefer using
the since this is about a specific country in a specific situation. I would use
a divided Germany for more hypothetical sentences.
Let's say it's 1945 and Germany has just lost the war. There are rumors going around that the Russians plan on keeping control of the eastern part of Germany while the Allies keep control of the western part. I can just imagine the following conversation:
A: Have you heard that Germany may be split in half because the Russians plan on keeping control of the eastern part?
B: Yes, I have. I think a divided Germany will create enormous problems for all of Western Europe. I hope this doesn't happen.
Anyway, that's my take on this point, Izzy. So even though both articles can be used, I'd prefer the definite article in the context of that page.