Re: Please help me identify the Subject
The grammar in original is wrong if it is supposed to be a complete sentence. And it's too long to be a proper headline. So I don't know what the author had in mind.
Originally Posted by EEL
The subject is problem. It's in the passive. We don't know who is addressing (trying to fix) the problem, because the people are are "doing" something are not named. However, the grammatical subject is problem. A problem is being addressed.
A very, very serious problem in Russia is the complete subject.
You are quite correct to add the "is." It's not grammatical (as a full sentence) without it.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.