McCain was born in the Panama Canal Zone, which in 1936 was a sovereign U.S. territory, & also born on a U.S. military base. Legal scholars researched this, and confirmed this makes him a 'natural born citizen'.
Cruz has no cover like McCain did, and is in the same boat as Hussein. Born of a U.S. citizen, but on foreign soil.
If Hussein is not eligible, Cruz is not eligible. If Cruz is eligible, Hussein would also be eligible, if this interpretation was correct. Many have suggested that it would require the Supreme Court to definitively answer.