Project Vista looked at improving U.S. tactical warfare capabilities. Oppenheimer was a late addition to the project in 1951 but wrote a key chapter of the report that challenged the doctrine of strategic bombardment and advocated smaller tactical nuclear weapons which would be more useful in a limited theater conflict against enemy forces. Strategic thermonuclear weapons delivered by long-range jet bombers would necessarily be under the control of the U.S. Air Force, whereas the Vista conclusions recommended an increased role for the U.S. Army and U.S. Navy as well. The Air Force reaction to this was immediately hostile, and it succeeded in getting the Vista report suppressed.