the words "all is not"
The decision ultimately rests with the president. But, if he decides to build his library outside Chicago, all is not lost for the Windy City.
What does "all is not" mean in this sentence?

Question

the words "all is not"
The decision ultimately rests with the president.  But, if he decides to build his library outside Chicago, all is not lost for the Windy City.
What does "all is not" mean in this sentence?

Answer

All is not lost for the Windy City = there are other options. Simply, the city is not doomed just because there is no library. Another example is in this link:

"Europe might be in bad shape but all is not lost" = "Europe might be in bad shape, but there are still positives!"

http://video.foxbusiness.com/v/3939001575001/europe-might-be-in-bad-shape-but-all-is-not-lost/