If I remember correctly, the number of F-18s we originally purchased was 140. That number came out of a calculation related to an existing threat to Canada, which was a Soviet bomber air-launched cruise threat. You then had to calculate the number you might need also in terms of our foreign commitment to NATO and what we could deploy and then sustain out there, if we were in a lengthy campaign rotating those forces.
One also has to ask what the capability of an F-35 is relative to the capability of an F-18, and the argument is that the capability is much greater and you can do with fewer. But I don't see that there is any shrinkage in the roles we can play by cutting the F-35 by the 30 or 40.