According to the New York Times, Fred Thompson has repeated the false claim that tax cuts increase revenue:
An analysis by the Congressional Joint Committee on Taxation, which looked into the kind of plan Mr. Thompson proposed, found that the federal government would stand to lose at least $2.5 trillion in revenue over 10 years.
But Mr. Thompson, a former senator from Tennessee, said in an interview yesterday on “Fox News Sunday” that such studies “always overestimate the losses to the government” and that tax cuts would spur the economy, leading eventually to greater revenues.
Thompson made a similar claim back in April. And he's not the only one -- Giuliani (here and here), Mitt Romney, and John McCain are all on the supply-side bandwagon. Who cares that even Bush administration economists think it's nonsense?