I'm not the first to suggest the Essenes of Josephus were the Herodians of The Gospels. The objections to that claim are dependent entirely on the assumption that the Dead Sea Scrolls were written by the Essenes. Since those scrolls are very seemingly the product of a separatist sect that wanted nothing to do with any Government ruling in Jerusalem.
But objections to that identification are common, I own the DSS translation done by Michael Wise, Martin Abegg JR., and Edward Cook. Their introduction lays out many of the flaws in that theory, but their own theory is that the Qumran community were a sub-sect of the Sadduces which I'm not sold on either.
There is also the theory that those caves were simply used to hide scrolls form many different origins as the fall of Jerusalem in 70 AD approached. I'm sure you can find online articles about all these theories.
I think they could have been Essenes, but if they were they were a peculiar group not representative of the whole. The biggest problem with the Essene theory to me is that Josephus clearly tells us the Essenes did not marry, while the Qumran community clearly did marry. But Josephus does at one point refer to a group of "marrying Essenes", maybe those are the Essenes who wrote the DSS, I don't know.
What I do know is Josephus divides the Jews of pre 70 AD Judea into three major sects, The Pharisees, the Sadducees and the Essenes. (And then later the Zealots sprung from the Pharisees, and the Sicari from the Zelots).
The Gospels mention often the Pharisees and Sadducees, but by that name at least never the Essenes. However Matthew 22, Mark 3 and Mark 12 seem to similarly depict the Jews of Jesus day as having three major sects, those two and the Herodians, with no group known by that name mentioned in Josephus. So the Clark Kent rule tells me the Eseenes are probably the Herodians.
Josephus account of the rise of the Essenes revolves around a fellow named Menahem, in Antiquities Book 15, Chapter 10 Section 5.
Now there was one of these Essens, whose name was Manahem, who had this testimony, that he not only conducted his life after an excellent manner, but had the foreknowledge of future events given him by God also. This man once saw Herod when he was a child, and going to school, and saluted him as king of the Jews; but he, thinking that either he did not know him, or that he was in jest, put him in mind that he was but a private man; but Manahem smiled to himself, and clapped him on his backside with his hand, and said," However that be, thou wilt be king, and wilt begin thy reign happily, for God finds thee worthy of it. And do thou remember the blows that Manahem hath given thee, as being a signal of the change of thy fortune. And truly this will be the best reasoning for thee, that thou love justice [towards men], and piety towards God, and clemency towards thy citizens; yet do I know how thy whole conduct will be, that thou wilt not be such a one, for thou wilt excel all men in happiness, and obtain an everlasting reputation, but wilt forget piety and righteousness; and these crimes will not be concealed from God, at the conclusion of thy life, when thou wilt find that he will be mindful of them, and punish time for them." Now at that time Herod did not at all attend to what Manahem said, as having no hopes of such advancement; but a little afterward, when he was so fortunate as to be advanced to the dignity of king, and was in the height of his dominion, he sent for Manahem, and asked him how long he should reign. Manahem did not tell him the full length of his reign; wherefore, upon that silence of his, he asked him further, whether he should reign ten years or not? He replied, "Yes, twenty, nay, thirty years;" but did not assign the just determinate limit of his reign. Herod was satisfied with these replies, and gave Manahem his hand, and dismissed him; and from that time he continued to honor all the Essens. We have thought it proper to relate these facts to our readers, how strange soever they be, and to declare what hath happened among us, because many of these Essens have, by their excellent virtue, been thought worthy of this knowledge of Divine revelations.So Josephus paints a pretty clear picture of the Essenes being politically tied to Herod. Josephus had also said as much at the end of the section just before this.
This Menahem of Josephus is also thought to possibly be the same as the Menahem The Essene of the Talmud. According to Mishanah Tractate Hagigah 16b he was the original Zugot with Hillel but left the Sanhedrin and was replaced by Shammai. The Jerusalem Talmud says he left to be appointed to a position in the Government.
In The Gospels the Herodians seem to be kind of allied with the Phairsees, and The Talmud paints a similar picture of the Essenes given Menahem's connection to Hillel.
It may be they were called Herodians only by certain non Essenes, and that label had gone out of use by the time Jospehus started writing.
February 25th 2016 Update: Beothusians
Another sect sometimes speculated to be the same as the Essenes partly on the grounds of both never showing up in the same source, are the Beothusians. Apparently Talmudic sources only mention the Beothusians while Josephus only mentions the Essenes. Of course as mentioned above a key Essene figure, Menahem, is possibly mentioned in the Talmud. While the Kohen family linked to the Beothusians are talked about in Josephus. But yet as a sect it seems only Josephus knows the Essenes and only the Talmud knows the Beothusians.
Well the relevance here is that the Beothusians are also not mentioned in the New Testament, and the Herodians are also not mentioned in the Talmud, at least not by those names.
The Family of High Priests linked to the Boethusians are also linked to Herod. Simon ben Beothus was appointed by Herod, and was one of the longer lasting High Priests Herod appointed. And Herod married his Daughter.
So perhaps the Boethusians can also be the same as the Herodians, and thus The Essenes were known by three names at least. Perhaps only Josephus called them what they called themselves (he claimed to have spent some time studying under all three sects, so he could have had some inside knowledge of each even though he ultimately chose to be a Pharisee). While other people tended to call them by the names of significant people they were linked to. Like how Catholics don't call themselves Papists, and originally at least Protestants didn't call themselves Lutherans.
But, a key difference is that the Boethusians=Essenes connection is viewed as possibly supported by the DSS=Essenes connection, while as discussed above that is viewed as an obstacle for the Herodians=Essenes view. Again, it may be that the DSS were written by a specific sub group of the Essenes not representative of the whole.
I want to diverge further on the subject of the family of Simon ben Beothus. It is somewhat well known that this family came from Alexandria just before Herod put them in power. What isn't as well known is what Josephus says in Antiquities Book 19 Chapter 6 Section 2.
"And when Agrippa had entirely finished all the duties of the Divine worship, he removed Theophilus, the son of Ananus, from the high priesthood, and bestowed that honor of his on Simon the son of Boethus, whose name was also Cantheras whose daughter king Herod married, as I have related above. Simon, therefore, had the [high] priesthood with his brethren, and with his father, in like manner as the sons of Simon, the son of Onias, who were three, had it formerly under the government of the Macedonians, as we have related in a former book. "Which seems to imply this family descended from Onias III, most likely via Onias IV. Which is interesting in light of theories that the "Teacher of Righteousness" of the DSS was a rightful High Priest robbed of his position, and that could easily have been Onias IV.
Because of how sects can often change over time, there is no guarantee Simon ben Beothus would have approved of all the doctrines The Talmud winds up attributing to this sect. Or what this sect itself believed by a generation or two later.
The possibility that Simon Beothus might have been the first High Priest of the line of High Priest Jeshua of the books of Ezra and Zechariah since the time of Antiochus Epiphanes. Makes me very open to the possibility that he was the same person as the Simeon of Luke 2's account of Jesus presentation in The Temple. Many have suggested only a High Priest could have done what he did. And because he's called "Just" some have even theorized he's part of the basis for the Talmud's Simon The Just.
Because Simon Beothus was removed and replaced by a son while still alive. He may have been viewed as still a co High Priest for awhile similar to how Ananias was as refereed to in the Gospels.