Suppose a Federation ship somewhere stumbles over a (stable) portal that transports ships back and forth to another stellar neighbourhood, which is not recognised (at first). Upon arriving there, a peaceful race is found, approximately being on a Federation level of development. Their and Federation values seem to largely coincide so cordial relations are begun. They satisfy all conditions for Federation membership and after a short time they opt for it, so the admission process is begun.
However, some time into this process, it is discovered that the portal doesn't transport ships primarily through space, but through time, let's say to 1.5 billion years in the past (this isn't noticed at first since 1.5 billion years is enough to alter the stellar neighbourhood beyond recognition (*) ) -- in our time, the race proves to be long, long extinct. Would this be an obstacle for the Federation to admit said society given that all kinds of ties already have been established, or would the Federation still recoil because of "mucking with the timeline"?
(* Probably they would still immediately recognise the fact by comparing positions of other galaxies, such as M31 and other members of the Local Group, but let's disregard that in order for this scenario to work.)
However, some time into this process, it is discovered that the portal doesn't transport ships primarily through space, but through time, let's say to 1.5 billion years in the past (this isn't noticed at first since 1.5 billion years is enough to alter the stellar neighbourhood beyond recognition (*) ) -- in our time, the race proves to be long, long extinct. Would this be an obstacle for the Federation to admit said society given that all kinds of ties already have been established, or would the Federation still recoil because of "mucking with the timeline"?
(* Probably they would still immediately recognise the fact by comparing positions of other galaxies, such as M31 and other members of the Local Group, but let's disregard that in order for this scenario to work.)