In my opinion tango can be danced in an embrace that is close, open or combination of both. It can be danced between a man and woman, two women, two men, or with a role reversal. It does not matter what clothes are worn, nor what music is played, assuming it has a rhythm conducive to the dance.

The essential quality of tango that must never be lost, tango's raison d'etre, or the 'baby in the bath water'  is - connection / communion with one's partner.  If people are not communing with each other in their tango, no matter how beautiful their moves, nor how on the music they are, their dance for me is not the type of tango that I want to dance or teach.