There is the claim that Christ is reigning in his kingdom now, that there is no future millennial reign of Christ before the final, eternal state. The millennial reign is now through the church. I believe it is significant that it is written that Jesus spent 40 days with his disciples after the resurrection, speaking on things pertaining to the kingdom of God: "... He also presented Himself alive after His suffering by many infallible proofs, being seen by them during forty days and speaking of the things pertaining to the kingdom of God." Acts 1:3 After Jesus told them to wait in Jerusalem for the Holy Spirit, they asked him if the kingdom would be then restored to Israel: "Therefore, when they had come together, they asked Him, saying, "Lord, will You at this time restore the kingdom to Israel?" Acts 1.6 How could they ask this after being taught about the kingdom of God, if there wasn't to be any restoration of Israel? Jesus doesn't correct them by saying that there will be no restoration of Israel, instead, he says the timing is not for them to know: "And He said to them, "It is not for you to know times or seasons which the Father has put in His own authority. But you shall receive power when the Holy Spirit has come upon you; and you shall be witnesses to Me in Jerusalem, and in all Judea and Samaria, and to the end of the earth." Acts 1:6-8
The disciples were not taught that there was no future restoration of Israel. They still expected it, and they were not corrected about it, except that the timing of it was not for them to know. hat they did not know was what God was going to do in the near future that would involve creating a new people for his purposes, being the gentile-jew assembly, commonly called the "Church." This "dispensation," being a new divine administration or stewardship, is only a temporal purpose of God in time. This is the time of the millennial kingdom of Christ. The kingdom is in a sense represented in the church, as Christ's ambassadors, but it is not the kingdom in the sense in which Christ will reign over the earth from Jerusalem over the nations in a manifested way, as we see in the Old Testament prophets, like Isaiah or Micah:
2 Now it shall come to pass in the latter days
That the mountain of the LORD's house
Shall be established on the top of the mountains,
And shall be exalted above the hills;
And all nations shall flow to it.
3 Many people shall come and say,
"Come, and let us go up to the mountain of the LORD,
To the house of the God of Jacob;
He will teach us His ways,
And we shall walk in His paths."
For out of Zion shall go forth the law,
And the word of the LORD from Jerusalem.
4 He shall judge between the nations,
And rebuke many people;
They shall beat their swords into plowshares,
And their spears into pruning hooks;
Nation shall not lift up sword against nation,
Neither shall they learn war anymore. Isaiah 2:2-4
1 Now it shall come to pass in the latter days
That the mountain of the LORD's house
Shall be established on the top of the mountains,
And shall be exalted above the hills;
And peoples shall flow to it.
2 Many nations shall come and say,
"Come, and let us go up to the mountain of the LORD,
To the house of the God of Jacob;
He will teach us His ways,
And we shall walk in His paths."
For out of Zion the law shall go forth,
And the word of the LORD from Jerusalem.
3 He shall judge between many peoples,
And rebuke strong nations afar off;
They shall beat their swords into plowshares,
And their spears into pruning hooks;
Nation shall not lift up sword against nation,
Neither shall they learn war anymore.
4 But everyone shall sit under his vine and under his fig tree,
And no one shall make them afraid;
For the mouth of the LORD of hosts has spoken.
5 For all people walk each in the name of his god,
But we will walk in the name of the LORD our God
Forever and ever. Micah 4:1-5
Futurists believe the kingdom is yet future, and not all of them would agree in an "already/ not yet" kingdom of Christ, but I believe you could say Christ reigns in a sense through the Church now, being that His kingdom authority is represented in the Church, but his manifested reign over the earth and nations is yet future. It will involve a restoration of Israel as a people and Nation in which Romans 11:16 is fulfilled when "all Israel will be saved": this is the restoration of the nation as a people of God in which all of its members will have salvation; it will be a new dispensation, being the millennial reign of Christ in which Israel will be restored as a people in special relationship and role for God. This will not change the terms of salvation any more than how someone was justified during the Old Testament times--Abraham was justified by faith, but it is a change of people for God's purposes in time. During the future reign of Christ, people will be identified by their nation, Israel being one of them:
"In that day Israel will be one of three with Egypt and Assyria—a blessing in the midst of the land, whom the LORD of hosts shall bless, saying, 'Blessed is Egypt My people, and Assyria the work of My hands, and Israel My inheritance.'" Isaiah 19:24-25
