A defiant Gov. Deval Patrick finally signed a welfare reform bill into law yesterday — only to say he won’t enforce key parts of the measure, drawing the wrath of lawmakers working to crack down on widespread abuses of the system.

Patrick, in a letter to lawmakers, said it’s “not feasible” to ban EBT purchases of frills such as liquor, cigarettes, lottery tickets and tattoos — and that “this administration will not enforce what cannot be enforced with respect to the use of EBT cards.”