What was missing from last night’s debate? Anyone? Bueller?

As I was puttering around this morning, there was something gnawing me about the debate last night.  None of the surface stuff — there was something amiss that I couldn’t place.  And then, going over the debate transcript, I realized it: 

Jim Lehrer didn’t ask a single question about China. 

Think about this for a second.  China is clearly the one country that can challenge the United States as a peer competitor in the next decade.  There are economic, regional, security, human rights, and global governance issues where Washington and Beijing don’t see eye to eye.  And there was no question that addressed any of this.  That is a whopper of an omission for a debate about foreign policy.   Question to readers:  what other foreign policy issues were not even discussed at last night’s debate?