This is from today's UFC 119 pre-fight press conference. I encourage you to watch the entire thing. Here's the gist of what's argued: there's nothing more the UFC can do. Make of that what you will. Clearly, though, the idea that the commission tests are falling short of a) catching all PED users and b) deterring further use is something White's not prepared to address at this point.
The other issue to underscore here is how White identifies the commission as the ultimate overseer. On a very real level, he's not exaggerating. Not only are commissions often drunk on their own power, the truth is the arrangement is mostly as White describes. At times some lose sight of the power hierarchy because of the UFC's familiarity with commission members or because of the perceived ease with which they are able to conduct operations. He is, however, legally at their mercy.
On the other hand, White's response doesn't directly address the central issue: why can't the UFC do more than or supplement the athletic commissions? I can't speak for White (although he attempts a response to that question at 7:52 here), but I assume he'd circle back to the idea that any further punishment exacted by the UFC in the event of a positive test would simply be abusive. The UFC (mostly) plays the good cop role, so why take bad cop from the commission? He also clearly states in the linked video from AOL that all the testing measures in the world won't stop athletes from taking these kinds of risks. White sees his and the UFC's only meaningful role as educator about potential risks. The problem is those responses don't cover the territory of a fighter testing positive through a UFC-backed WADA-style testing, but passing the commission urinalysis. When White asks "what more can I do?" he is talking about adding on to the commission's punishment. But what if the fighter passes a commission urinalysis and fails a WADA blood test the UFC paid for? Then what would the punishment be? And there are people who still think this wouldn't make the commission look bad?
You can make from this what you will. My sense is that Sonnen's popping positive has flirted with disaster, but is not big enough to truly force White's hand. Jim Rome is big media, but he's also something of a MMA mark. It will take something with substantially more fallout before changes are made. Champions have tested positive before, but not wealthy, elite fighters. The day a UFC figurehead pops is the day we may see more proactive measures, either from the UFC or the commissions or both. Until then, the policies as they exist remain intact. Steady as she goes.
More Dana White commentary on this issue after the jump.