Contingency planning is not the same thing as a policy reversal. Close, but not quite the same thing. Just in case we change our policy, we can implement the new policy in about twenty minutes. (Ballistic missile flight time.)
BTW, Eisenhower threatened to use nuclear weapons against China in order to end the Korean War. Truman used nuclear weapons against non-nuclear Japan. It isn't clear that any of these countries aren't aspirants to membership in the nuclear club. Becareful what you hope for.
Simple; Bush never gave them a chance. Most post-WWII administrations (Reagan's was somewhat of an exception) were afraid of the media reactions to everything they might do, and Clinton made it worse by intentionally leaking every potential policy change and/or having his pollsters test it to see its effect on his popularity rating before he ever implemented anything.
Bush, on the other hand, simply DID it. No leaks, no focus groups, not one iota of concern as to how much the psycholeftists and the professional Bush-haters in the news media might shriek about it. The decision was made before any of them even had a chance to open their giant mouths. And all their shrieking now isn't going to change it.
There are still a few remnants of this Washington Wussiness around - see how the Pentagon caved in on their plans for the Office of Strategic Influence after the media intentionally lied and spun about its purpose. But even that has a silver lining - the Pentagon will now merely do such things deep in the background instead of openly, a far preferable solution.
And you can be sure that as a result of this OSI mess, the White House now has the names of a few more Clintonoid generals over at the Pentagon that are going to be eased into early retirement. At the start of every war, there's always a ton of deadwood in the military that either cannot or will not adapt to the new paradigm, and it takes up to two years for them to all be identified and expunged. But it is happening.