I recently read Pope Pius XI's encyclical Quas Primas which established the Feast of the Kingship of our Lord Jesus Christ. The feast changed location after the Vatican Council II, and the focus changed noticeably, as Father Z pointed out a couple of weeks ago. However, our faith in the universal kingship of Jesus Christ cannot change due to the fact that his kingship simply doesn't manifest itself clearly or fully in our modern world. This kingship is not just personal and spiritual (i.e. confined to an individual's relationship to him through his Church), but it is a social kingship as well. Pope Pius XI made that very clear in his encyclical, and the Catechism still affirms it: "Thus, the Church shows forth the kingship of Christ over all creation and in particular over human societies." (CCC 2105)
Christ's universal kingship has two implications: 1) his kingdom is open to all, and 2) all people are subject to him. The first is obvious, the second might not be, but it is just as true: every person is subject to (and a subject of) the Lord Jesus Christ who is King. It is because of this that his kingdom is open to all. What strikes me as interesting is that every person (whether or not they accept Christ) is currently -- i.e., in this present life -- "in" the kingdom: no one is banished from the kingdom in this life (because there is always a chance to repent).
Thus, each person is connected to Jesus Christ, whether through his Church or not, and this because through the Gospel we are taught that in ministering to any person in their need, we are in fact ministering to Christ; thus, as the Catechism explains, even those "who have not yet received the Gospel are related to the People of God in various ways" (CCC 839, cf. Lumen Gentium 16). This means that Christ, as the benevolent king he is, relates to every single one of his subjects because he shares our common human nature (although in perfection), and so we encounter Christ in each and every person we minister to, regardless of whether they believe in him.
This does not mean that this simplest connection to Jesus Christ, this minimal relation to the People of God, is sufficient. If if were, Christ would not have charged his Church with preaching the Gospel to all nations and baptizing new members. It does mean that God has prepared all people (cf. CCC 843)for the reception of the Gospel, the "manifesto" as it were of our Lord and King.