A little history lesson:
God gives Torah to Moshe and Bnai Yisrael. During Moshe's lifetime, Jews follow Torah (with a few notable exceptions) - they had strong centralized leadership that kept them on the (pardon the cliché) straight and narrow. The same applied for the lifetime of Yehoshua Bin Nun. Then trouble started to happen. There was about a three and fifty year period during which the Jews kept falling off the bandwagon of Torah observance, falling into the trap of Avodah Zara and various other nasties. Each time they fell, we see there was no real leadership at the time. Then, they would get in trouble, God would send them a leader to bail them out and set them back on the Torah path, and things were good for a while. This happened several times, until Shmuel Hanavi came along, a powerful Shofet who once again set the Jews straight and kept them there. The Jews then asked for centralized leadership again, a king who, if he followed Torah dictates, would not be a sovereign dictator but an example of how a Jew should be and act.
So God, somewhat upset that the Jews can't get their act together without having to resort to needing a king, says "sure, you can have a king," and gives them Shaul, a young, and at the time, pious, humble, and shy man who would lead the Jewish army to what should have been a final, decisive battle against Amalek, where Amalek would be forever wiped out, thus bringing about Yemos Hamashiach and an end to all tribulations. This turned out to be a whopping failure as Shaul left Agag, the Amalekite king, alive, giving him time to sire a son whose descendant would be Haman. Oops. Of course, we did get Purim out of this!:) We also got a Holocaust out of it, too.
King, take two: Dovid Hamelech! This one worked! He conquered the land, fought off the Philistines with absolute finality, and he showed us he was human with human failings. However with all those failings, failings he was able to admit he had within him, he was still able to lead the Jewish people, show us what a great man can do, wrote/compiled Tehillim (he didn't write them all), and even aspired to build the Bais Hamikdash, having chosen the spot where it would eventually stand. His successor, Shlomo, completed the job and brought the Jewish people to an unprecedented era of peace and prosperity.
Next came Rechavam, Shlomo's son, who wouldn't let up on taxes, cheesed off the ten tribes, and drove them away. Yeravam ben Nevat became the first king of the ten tribes, and in a brilliant, though corrupt, political move, set up golden calves and told the ten tribes they no longer had to go up to Yerushalayim, thus spiraling the ten tribes into a downward decline of avodah zara and various other sins, a decline from which they would never recover and which would to the eventual golus and disappearance from history of those ten tribes. As soon as the Jews were told you don't have to do the Torah thing anymore, they went off and did what they wanted, despite so many warnings from so many Nevi'im, the most prominent of them being Eliyahu Hanavi.
The Davidic dynasty did fair better for a while, and there were shining moments of Torah Renaissance (Chizkiyahu and Yoshiyahu specifically). But eventually, this too failed, as the kings did not perform their duties as being shining examples of how a Jew should act. Some were outright idol worshippers who had the nation worshipping idols, while others were Torah observant but completely useless, allowing the two tribes to continue about their merry, idol worshipping ways. Finally, the Bais Hamikdash was destroyed, followed by a seventy-year golus to Bavel (now a lovely garden spot known as Iraq).
There is a Medrash that says when the Jews returned to Eretz Yisrael, the leaders captured the Yetzer Hara and blinded him to prevent him from ever tempting the Jews to commit sins like Avoda Zara. I have no idea what this Medrash means, as the Yetzer Hara, also known as Satan, has still managed to do a pretty good job at temptation. I think what really happened was the Jews grew up and realized how stupid idol worship actually is. This did not stop the Yetzer Hara from tempting Jews with other types of Aveiras, as we will see.
Next, along came the Knesses Hagedola, the Great Assembly, established by the last of the Prophets, Ezra Hasofer and Nechemia, the precursor to the Tanaic period, and began to set up guidelines. These guidelines would be expanded and expounded upon by the Tanaim, the first of whom was the last member of the Knesses Hagedola, Shimon Hatzadik. The Tanaim began the Mishnaic period, when major Halacha would be decided, many would argue with one another, and mostly, if not always, the Halacha would follow the majority. The Anshei Knesses Hagedola and the Tanaim began what we today as Torah She'be'al Peh - the Oral Torah/Tradition - Mesorah - the major reason many today tout as the excuse to do or not to do something, though it is conveniently forgotten when it becomes, well inconvenient (anybody ever wonder why turkey is considered kosher? There is no Mesorah for it whatsoever!). Most of these guidelines, later written down by Rabbi Yehudah Hanassi, the last of the Tanaim, were, as it says in the very first Mishnah in Maseches Brachos, "Kedai Le'harchik es Ha'adam Min Ha'Aveira" - to distance a person from committing a sin or (as is the actual case discussed in that first Mishnah) to make sure a person follows Torah Halacha, like saying Shema at the proper time.
I believe, for the most part, at least at first, Chazal had the right idea - let's prevent the tragedy and travesty of the era of the first Bais Hamikdash from happening again. They came in, saw the system the Nevi'im, people many orders of magnitude greater than the Chachamim (after all, they spoke to God!!), had set up was not working, and set up a new system, a system of oral tradition the core purpose of which was to keep the Jews on a Torah path. Did it work? To some extent, it certainly did. Jews historically have never really been interested in idol worship after the destruction of the first Bais Hamikdash. So, in a sense, I guess the Satan was "blinded" - prevented from causing Jews to worship idols anymore.
But did the new system work? Again, in some aspects, it certainly worked, but not in most. People still went around shucking off Ol Malchus Shamayim when the opportunity came along, as was the case with Hellenism. People began hating others needlessly, without cause or provocation, the classic reason of the why the second Bais Hamikdash was destroyed, as illustrated by the story of Kamtza and Bar Kamtza. Many groups splintered off from the "rabbinic mainstream," saying the rabbis had no right to dictate halacha not found in the Torah, the most famous of these groups being the Sadducees, Essenes, and the Christians (unfortunately, we all know where that went!). Could these developments have been avoided? Yes. If the rabbis had sat down with these groups instead of dismissing them out of hand, talked through the issues and came to agreements, perhaps many of these developments could have been avoided. Instead of pioneering a new system, as they had done hundreds of years earlier, they decided this was the only system possible and no one could change it. No one.
The lesson we're supposed to take from this: Chachamim decide Halacha. This stems, as I mentioned in an earlier post, from the often misquoted Possuk in Shoftim about following the psak of the shofet, a possuk often used to assert the complete control Gedolim, past and present, have exerted over decreeing what is the halacha, even though that possuk specifically talks about a Din Torah, not a carte blanche to do whatever any self proclaimed "Gadol" wants to do.
Next: Part Two of Bas Kol
