The Vision in trouble?

Ht from Instapundit on this article in Popular Mechanics by Tom Jones:

If Administrator Mike Griffin is responsible for this hard-eyed approach top NASA’s future, he is to be commended. But the constant tinkering with launchers and the cost and schedule difficulties still to be grappled with in getting the new Crew Exploration Vehicle off the ground will only exacerbate Congressional suspicions that NASA, faced with painful budget choices, is trying to low-ball the costs for its exploration plans. The agency tried the same tactic 15 years ago with the Space Station, and suffered a huge loss in credibility with the administration, Congress and the public. NASA knows it must not squander the Vision opportunity, but can it avoid a repetition of its past missteps? If America hopes to fly astronauts again once the shuttle retires, the answer must be yes.