For emergency use only, but part of the design requirements.
Never heard of this design requirement, but a thing is for sure : if that requirement was present it has been miss by production models by a very very very long margin.
The CIA was adamant that the Backfire (Tu-22M2) had a flight range of 6,000km which made it a strategic bomber for a one way mission. The actual range was much less than that. The new engines in the Tu-22M3 improved performance significantly and there are suggestions that 6,000km is an underestimate, but either way both aircraft lost their inflight refueling probes.
CIA and DIA Tu-22M3 range estimations was obviously referred to combat range.
The US Defense Intelligence Agency (DIA) initially had estimated the Backfire's unrefuelled combat radius at approximately 5,000 km, sufficient to pose a strategic threat to the United States, while the Central Intelligence Agency (CIA) estimate was about 3,700 km. subsequently the DIA estimate was reduced to about 4,000 km, and the CIA estimate to 3,360-3,960 km.
Adamant was also the assertions of the same Chief Designer of "Backfire":
During the mid-1990s the author discussed the Tu-22M3 with Levanovich, who was adamant that the production aircraft had a hi-hi-hi combat radius of 4,000 km (2,160 NMI) with a payload of three Kh-22M/AS-4 missiles, well in excess of then current Western estimates.
Try to guess why the first airbase foreseen to be destroyed, in the chance a "growing intensity" not-nuclear conflict with NATO, was just Elmendorf Air Base
Its destruction would have left open the entire continental USA and its entire industrial base - main Shipyards both on West and East Coast, main Airfields, Command and Control sites, Space and Air defense radars etc...-, devoid even only of the guise of a credible IAD ,to even the most simple conventional cruise missile attacks.
The event would have likely forced USA to accept a cease-fire agreement at favorable terms for URSS.
Capability ,by part of the supersonic fleet of TU-22M3, to endanger ,unrefueled, both CVBG in open Pacific Ocean (well outside coverage of NORAD based USAF coverage) and shipyard and dock basing in the entire West Coast was absolutely structural in its strategic concept of operation.