When Senator Roth introduced a bill for an individual retirement account with no upfront deduction, part of the superficial appeal was that the revenue damage to the budget came outside the budget window. He called it the IRA Plus. My boss at the time (1988 or 1989 or 1990), Senate Finance Chair Lloyd Bentsen, said that PLUS stood for “Pay Later, Uncle Sam.” That retort became Tax Notes’ quote of the week. The name IRA Plus disappeared, and Senator Roth’s name got attached to what became the Roth IRA.
UPDATE: It was 1989, according to https://en.wikipedia.org/wiki/Roth_IRA.
The Center for New Revenue 