In 1957, the American missile programme was suffering from the Administration's 'economy measures'.
The US President declared in March 1957 that the approved number of missiles from each programme (ICBM, IRBM and MRBM) be ready "at the earliest practicable date".
This was a change from earlier guidance which called for the missiles to be ready "at the earliest possible date".
Major General Samual Brentnall (Assistant Chief of Staff for guided missiles) warned the Eisenhower administration that cuts would lead to a serious 'missile gap' (between the US and USSR) by about 1960
The economy measures slowed the production rate and therefore the operational date of the various missile systems.
The USAF Thor missile system was in competition with the Army's (more developed) Jupiter missile system.
The Army's Jupiter missile and the USAF's Thor....both with similar ranges .
Jupiter was designated as a MRBM with a range of 2400km
Thor was designated as an IRBM with a range of 2850km
Thor missile production was slowed to provide just enough missiles for the flight test schedules.
Contracts for ground based launch systems were suspended or cancelled.
Thor would remain in a "Research & Development" state until the Secretary of Defence and the President decided which system would go into the operational inventory.
US Secretary of Defence.......Charles E Wilson