Actually, Senator Bill Heffernan was precisely the right person to draw our attention to the word “barren”. While using the word in its best-known, if somewhat tastelessly Jacobean, context — “not producing or incapable of producing offspring” — its other meanings describe the senator to a tee:

Unproductive … unfruitful … without capacity to interest or attract … mentally unproductive … dull … stupid … not producing results … fruitless … destitute … bereft … lacking …

Well done, Bill. There’s no member of Parliament better qualified to talk about that word.