What relationship does the Catholic Church perceive to exist between itself and various Protestants (the baptized ones who still accept their faith)?
Validly baptized Protestants are regarded as true Christian brothers and sisters who are in imperfect relationship with the Church. The nature of the imperfections is as varied as Protestantism itself. The idea at work here is that the faith is an incarnational thing, not just a “spiritual” (disembodied) thing—just like Jesus himself. Thus, it is possible to be out of union with the Church “bodily” (structurally, sacramentally, liturgically), yet still have a spiritual unity with the Church. Likewise, it is possible to be “bodily” united to the Church yet cease to be in communion with her spiritually (as an apostate Catholic is if he keeps going to Communion yet rejects the creed or continues unrepentant in grave sin). The latter form of disunity with Church is more serious than the former.