As long as G.W.'s policies remain ambiguous, every TV ad is a stealth Bush ad.
If G.W.'s policies remain obscure, then no TV ad can be a stealthy Bush ad.
mnli hypothesis: If G.W.'s policies remain obscure, then no TV ad can be a stealthy Bush ad. premise: As long as G.W.'s policies remain ambiguous, every TV ad is a stealth Bush ad.