Being politically astute, even in her dotage, Baroness Thatcher was aware what contention that could create.
"the state of one who dotes," c.1300; see dote + -age. Originally of all sorts of mental impairment, not just that resulting from old age. First recorded late 14c. for "senility."
dotage dot·age (dō'tĭj)n. The loss of previously intact mental powers; senility. Also called anility.