A great idea indeed...if you were for total nuclear destruction.
I think the SLAM was designed to be a “middle-finger” weapon, launched only after a first strike was perpetrated against us, and we wanted to ensure that the Soviet Union was nothing but an irradiated wasteland, useful for no one.
Pretty much an affirmative on that as I remember it.
Just to confirm your supposition:
It was a Dr. Stranglove worthy Doomsday equivalent weapon.
http://www.whiteeagleaerospace.com/the-missile-from-hell/
“The heart of the Project Pluto missile was the nuclear-fueled ramjet. An unshielded nuclear reactor, code named TORY, was devised, built and successfully tested. Testing was conducted at a special-purpose test site in Nevada. In its Tory II-C configuration, the SLAM ramjet produced over 500 megawatts of power in 5 minutes of continuous operation during a test conducted in May of 1964.”
(snip)
“Coupled with the above practical concerns of SLAM flight testing were growing political and mission obsolesence issues. Pentagon officials ultimately deemed Project Pluto as being highly provocative to the Soviet Union in the sense that the communist super power might feel compelled to develop their own SLAM. Further, American missilery was quickly developing to the point where ICBM-delivered warheads would do the job and at a lower per-unit cost.”