If we assume that the US Govt operates in a relatively non-corrupt manner, then for the TSA to decide that DL cannot operate their route to NBO at short notice, would require some degree of accountability withiin the US Govt.
Either the TSA is acting without sufficient controls, or there is something which the US Govt security apparatus knows which we don't know and cannot be told.
One assumes that the people running the TSA are aware of the need to demonstrate accountability and that sufficient controls are in place, so as to enjoy the confidence of both the American public as well as the upper echelons of the US Executive.
The TSA are presumably aware that if the American public lose confidence in the existing controls and accountability process, then there are likely to be significant ramifications.