They were initially envisaged for two different roles: TOW for infantry (HAW) role and Shillelagh for combat vehicle weapon system (CVWS) role. Already in 1962, it was proposed that whatever design was more successful, and could be adapted for both roles, it should be pursued alone. However in August 1962, MICOM advised that conclusive evidence of the feasibility of using TOW in the CVWS role (due to the issue of pulling wire from a closed breech tube) would not be available before December 1962, whereas the decision regarding the system(s) to be developed for the CVWS and HAW roles was scheduled for mid-October or earlier.
Although the TOW and Shillelagh very likely could be developed in a version which would be usable in both the HAW and CVWS applications, the selection of either one to fulfill both roles would mean the acceptance of less than the best system for one role or the other. This stemmed from the fact that the Shillelagh and TOW had specific limitations which were intrinsic to their respective concepts. The consequences of Shillelagh limitations were more pronounced in the HAW application and the consequences of the TOW limitations were more pronounced in the CVWS application. Moreover, there was some doubt that the economic and logistic advantages would offset the performance penalties inherent in such a system. For these and other reasons, Balistic Reserch Laboratory favored the development of both systems, and this was corrobated by Hudges Aircraft study too. Seven years later, however, the TOW/Shillelagh competition again surfaced and very nearly caused the cancellation of the TOW program.
In the fall of 1969, MICOM learned that higher headquarters were again giving consideration to replacing the TOW with the Shillelagh system. The Department of the Army first reduced the budget for 1970 because of delays (although by that point the system was maturing and reaching requested set requirements). Then the above mentioned House Armed Services Committee cancelled the entire program from the FY 1970 budget on 25 September 1969. The committee suggested that the guidance and control elements of the Shillelagh could be repackaged so that Shillelagh could replace the more expensive TOW in its ground role. DDRE also concluded that this adaptation might present potential cost savings to the Government.
Secretary of the Army wrote to Congress and argued that, in full production, the cost of TOW would be about equal to the Shillelagh and that converting the latter to the ground role would be expensive in terms of time and money. Given the urgency of HAW requirement, and expected three to four-year delay if Shillelagh was to be converted, Congress eventually restored the TOW program in November 1969, although one of the congressmen defined the TOW a "billion-dollar boo-boo" and a "wasteful duplication" of the Shillelagh missile which was already in production. Congress opposition versus Army support for TOW continued into 1970, extending debate into what missile should be used in helicopter role, being eventually subdued in 1971 when TOW proved to be a cheaper solution and excellent weapon in service.
Edited by Nikolas93TS, 03 July 2017 - 0727 AM.