HELP with old cabled oak

[SINGLE-JACK]

UUUUHHH, really? What did they find a piece of old pole guy cable laying on the curb?
If you want to try what Treeseer mentioned I recomend using dynamic tree support rope. Its so easy to do by yourself too, don't need all those tools and steel cable being sent up.

Cut the cable that system that ain't worth nothing that looks like skinned extension cord , that tree didn't need one in the first place a little pruning is worth any cable and less damaging , the tree swallowed that cable a long time ago and the damage is done , so why remove it?

I think TMD nailed it; "a piece of old pole guy cable" ... recognized the "U" cable connection seen everywhere on utility poles?

jomoco seems to have the most rational advice about saving the tree ... but SD, CA a long commute, lol.