You wrote: "The idea of a Holy Bloodline, IMO, negates the message that Jesus brought, ie, that the future Kingdom will be born out of the spirit and not out of man made political rulership."
Rob, to some extent, I agree with you but lets see what the scriptures tell us. There IS a holy bloodline and it is important, but it IS NOT the bloodline that is being discussed here.
There are two scholars and Archaeologists, both of whom belong to the Society of Antiquities, Scotland. One is Sir Lawrence Gardner, April AOM here the GHB site, and E. Raymond Capt. Both have done extensive study and research into the bloodlines of the Kings of Scotland. Both discovered that the Kings of Scotland and later England are descended from the throne in which King David himself sat on, and the Bible itself supports their theories.
The scriptures tell us that there will be both a spiritual and physical kingdom complete with the "King" and government rule. Only this government rule will be by Jesus Himself, not by the rulers of this current world order. Right now, we are under spritual development by the Holy Spirit, but Jesus taught that He would someday return to rule with the "rod of iron".... an earthly kingdom. Why? Because HE IS the HEIR to the literal throne of David. And if He is heir to the throne of David, then His throne must still exist in order for Him to claim it.
Let's examine the scriptures....
Isa 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.
Isa 9:7 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.
(These scriptures are repeated in the Gospels.)
Zec 3:8 Hear now, O Joshua the high priest, thou, and thy fellows that sit before thee: for they [are] men wondered at: for, behold, I will bring forth my servant the BRANCH. (Jesus is referred to here as the BRANCH. The highest branch is symbolic for the Royal House of Judah or the line of kings.)
Zec 6:12 And speak unto him, saying, Thus speaketh the LORD of hosts, saying, Behold the man whose name [is] The BRANCH; and he shall grow up out of his place, and he shall build the temple of the LORD:
1Ki 8:25 Therefore now, LORD God of Israel, keep with thy servant David my father that thou promisedst him, saying, There shall not fail thee a man in my sight to sit on the throne of Israel; so that thy children take heed to their way, that they walk before me as thou hast walked before me.
1Ki 9:5 Then I will establish the throne of thy kingdom upon Israel for ever, as I promised to David thy father, saying, There shall not fail thee a man upon the throne of Israel.
Eze 17:1 And the word of the LORD came unto me, saying,
Eze 17:2 Son of man, put forth a riddle, and speak a parable unto the house of Israel;
Eze 17:3 And say, Thus saith the Lord GOD; A great eagle with great wings, longwinged, full of feathers, which had divers colours, came unto Lebanon, and took the highest branch of the cedar:
Eze 17:4 He cropped off the top of his young twigs, and carried it into a land of traffick; he set it in a city of merchants.
Eze 17:5 He took also of the seed of the land, and planted it in a fruitful field; he placed [it] by great waters, [and] set it [as] a willow tree.
Eze 17:6 And it grew, and became a spreading vine of low stature, whose branches turned toward him, and the roots thereof were under him: so it became a vine, and brought forth branches, and shot forth sprigs.
Thus saith the Lord GOD; I will also take of the highest branch of the high cedar, and will set [it]; "I will crop off from the top of his young twigs a tender one, and will plant [it] upon an high mountain and eminent:" In the mountain of the height of Israel will I plant it: and it shall bring forth boughs, and bear fruit, and be a goodly cedar: and under it shall dwell all fowl of every wing; in the shadow of the branches thereof shall they dwell.
Now who is the "tender one of the young twigs". If you understand the symbolism here, you will find that the "tender twig" is a feminine child. This is referring to the daughter of a King. Who is this daughter? Furthermore, we must also understand that the Bloodline of David not only extends through the sons, but also through the daughters as well.
After Babylon invaded Israel, Zedekiah was made king. He later rebelled against Babylon, but was overcome. He and his sons were murdered, because Nebuchanezzar sought to destroy the Royal House of David and cut off the bloodline. (But we know this bloodline had to continue because Jesus was born later of this bloodline.) The Prophet Jeremiah escaped to Egypt with Zedekiah's daughters and archaelogy then traced them to Scotland. One of the daughters is named Tia Tephi and her daughter was "Scota" from where the name Scotland is derived. There are other variations of the story, but this is the most common.
Jeremiah is buried in Ireland under the name "Ollamh Fodhla". Here's one site that explains further....
Both Gardner and Capt have written books on this subject. Very interesting stuff.