The Navy found an unlikely ally in the Army, who were concerned that Red Heathen was too difficult to move to in a single stage and suggested that Seaslug might be the basis for a more immediate medium-range weapon that could be used both on land and sea. The DPRC also began to have concerns about guiding Red Heathen at its maximum range. In September 1948 they agreed to develop Seaslug "as a matter of insurance", before further upgrading it in 1949 to "top priority". As a result of these changes, the program was seen as having two stages, Stage 1 would deliver missiles in the mid-1950s with roughly range with capability mostly against subsonic targets, and a Stage 2 of the early 1960s would have a greatly extended range on the order of and able to attack supersonic aircraft.