|Believing Israel||Unbelieving Israel||Believing Christians||Unbelieving Christians||Nobody|
There are really only two basic views, of which the others are variations. Succinctly, in the Reformed view, the church is true Israel in most meaningful senses (except ethnically, of course). Dispensationalism divides the people of God into two distinct and separate bodies, Israel and the church. The Dispensational view raises numerous difficulties, and there is no single coherent Dispensational position that reconciles them all. Closing the gap at one place seems to rip it open in another.
The first view listed above seems plausible to me, but I prefer the fourth. The second view seems to me to be fraught with difficulty, and I personally can see no way in which it could have arisen from the scriptures themselves, nevermind from Romans 11 in particular. It appears to me to be more a side-effect of Enlightenment philosophy than a necessary inferrence from scripture. The third view appears to be an attempt to evade the problem via triangulation, and I think it forces you to read an awful lot into the passages that treat the subject.
"The root refers to the blessing promised to Abraham in the Abrahamic Covenant. That blessing was the promise of Christ (John 8:56; Heb. 11:8-10). This means that both Israel and the Church are constituent parts of the one covenant of grace."
"The illustration Paul uses is one of organic connection, and not discontinuity." [em]
"On what exegetical basis, then, do you limit the covenantal blessings and promises which will proceed from that root to the ingrafted branches?" v.17 "…He (Paul) does not even hint that believing Gentiles have access only to the soteriological sap."
"Consider how Paul’s illustration would have to go in order to match your position. 'God established the Abrahamic root. From this root, the branches of national Israel grew. God then cut off all these Jewish branches, leaving a completely naked stump. Then He grafted in the believing Gentiles, along with some believing Jews He had just cut out – so that they could be in the tree, but not part of Israel. At some future date, the tree will be completely shaved again, removing all the believing Gentiles to an unspecified place. Then distinct national Israel will be grafted back in again.' This view has strengths, but being in Romans 11 is not one of them."
I think Paul makes it clear throughout his teaching that there is only one true Israel, that it is essentially spiritual in nature, and that the church is where "the Israel of God" is found since Pentecost. For example, note his use of singulars and plurals in the following passage. Try to follow his train of thought as a single argument from beginning to end:
Eph. 2:11-15 (ESV)
Therefore remember that at one time you Gentiles in the flesh, called "the uncircumcision" by what is called the circumcision, which is made in the flesh by hands -- remember that you were at that time separated from Christ, alienated from the commonwealth of Israel and strangers to the covenants of promise, having no hope and without God in the world. But now in Christ Jesus you who once were far off have been brought near by the blood of Christ. For he himself is our peace, who has made us both one and has broken down in his flesh the dividing wall of hostility by abolishing the law of commandments and ordinances, that he might create in himself one new man in place of the two, so making peace, and might reconcile us both to God in one body through the cross, thereby killing the hostility. And he came and preached peace to you who were far off and peace to those who were near. For through him we both have access in one Spirit to the Father. So then you are no longer strangers and aliens, but you are fellow citizens with the saints and members of the household of God, built on the foundation of the apostles and prophets, Christ Jesus himself being the cornerstone, in whom the whole structure, being joined together, grows into a holy temple in the Lord. In him you also are being built together into a dwelling place for God by the Spirit.
Compare I Peter 2:4-10, remembering that it was written specifically to Jewish believers.
If Israel and the Church are branches on the same tree, and are one body, one new man, one chosen nation, one royal priesthood, one household, one structure built on one foundation, and one holy temple being built up together as the dwelling place of God, then how can we be two separate people of God?
Consider also that God calls both Israel and the Church his bride. Does He now have two wives, or is He divorced?
Finally, note that the Greek word ekklesia, translated "church" in our English New Testaments, was already in common use among the Jews at the time of Christ and the apostles, and used by them to refer to the nation of Israel. It is the word used in the Septuagint -- the Greek translation of the Hebrew Old Testament -- for "the assembly" of Israel, "the congregation" of the righteous, and similar terms. For Jews, Israel, collectively, was the ekklesia, the church. In the mind of any 1st century Jewish reader, the use of the word "church" to refer to all believers in Christ would have meant that Israel had been expanded to include believing Gentiles, not that some new organization had been established. If the New Testament writers had meant to overcome that natural conclusion, they would have had to go to great lengths to explain why. Technically, this is an argument from silence, but it's one of those pronounced silences, a meaningful silence. That is, if they had meant to make some hard distinction between Israel and the church, it would have been negligent for them (and by implication, for the Holy Spirit) to refer to believers of all ethnicities collectively as "the church" without making a major effort to show that they were using the term unconventionally.
In light of the apostles' teaching that Israel and Gentile believers are part of the same olive tree, and are one people in perhaps all possible meaningful senses except after the flesh, they would have to have given us specific teaching showing that we are, in some other significant sense, not the same people of God, if they wanted us to believe that. I can't find that teaching anywhere in scripture, and Paul's example of the olive tree appears to undercut it deeply, if not to make it altogether untenable.