Jesus is to sit upon the throne of David:

Isaiah 9:6 For unto us a child is born, unto us a son is given: and the government shall be upon his shoulder: and his name shall be called Wonderful, Counsellor, The mighty God, The everlasting Father, The Prince of Peace.

  7 Of the increase of his government and peace there shall be no end, upon the throne of David, and upon his kingdom, to order it, and to establish it with judgment and with justice from henceforth even for ever. The zeal of the LORD of hosts will perform this.

Acts 2:29 Men and brethren, let me freely speak unto you of the patriarch David, that he is both dead and buried, and his sepulchre is with us unto this day.

  30 Therefore being a prophet, and knowing that God had sworn with an oath to him, that of the fruit of his loins, according to the flesh, he would raise up Christ to sit on his throne;

Also, Jesus is to rule the nations with a rod of iron:

Revelation 19:15 And out of his mouth goeth a sharp sword, that with it he should smite the nations: and he shall rule them with a rod of iron: and he treadeth the winepress of the fierceness and wrath of Almighty God.

So why do the replacement theology folks say that Jesus is doing both, now, from heaven?

Do they really think that David's throne has been transferred to heaven, no longer to be on earth?

Do they really think that Jesus is currently ruling the nations with a rod of iron, from David's throne in heaven?

If so, then is that rod of iron not doing its job, for Jesus?

Is the islamic republic of Iran, that worships a false god, sponsors international terrorism, and wants to destroy Israel, really being ruled by Jesus at the moment?

How about atheist North Korea, that imprisons and tortures Christians, is it really being ruled by Jesus at the moment?

Isn't the throne of David what Jesus will sit on, here on the earth, during the thousand year kingdom?

Why do they think that Jesus is sitting on a different, earthly throne, in heaven, when he told us that he is sitting with the Father in his throne?

Revelation 3:21b even as I also overcame, and am set down with my Father in his throne.

Then, later, after the thousand year kingdom, in the new Jerusalem, it will still be that one throne of both the Father and Jesus )both God and the Lamb):

Revelation 22:1 And he shewed me a pure river of water of life, clear as crystal, proceeding out of the throne of God and of the Lamb.

  3 And there shall be no more curse: but the throne of God and of the Lamb shall be in it; and his servants shall serve him:

.