We had a democratic republic with fair elections at some point in time

What is a "democratic republic?" A representative government where the people elect their representatives? Who are the people with the voting power? From what group of people are the representatives elected from?

When the country was first made with the signing of the Constitution in 1787, the only people who were allowed to vote or be representatives were land owners. How many people owned land? About 3% of the population. Every single one of them descended from a long line of wealthy landowners, they themselves descended from the Lords of Britain and Holland, AKA the Aristocrats (a group that remains coherent by extreme pressure to marry other Aristocrats, their cousins)..

The laws made at the time regarding land ownership in this new country they had created stated you could only buy land in 320 acre lots. This made buying land prohibitively expensive, ensuring only the very wealthy ever bought any land. The land ownership restriction on voting changed a few decades later, and it became easier to buy land eventually, especially with the "western frontier" migration, but this is how it began, and how it was for the first few decades. Other fuckery ensured that the power remained in the aristocracy after the land things changed. I could go through a blow by blow of every piece of legal fuckery that led to what we have today, where the Aristocrats (and specifically, a subset of the Aristocrats, the Cabal) own everything, but it would take a GREAT deal of time.

That theory has no proof to it and is pure speculation

I have my report, if you wish to read it. It shows how there exists a single corporation in the world, and a single body of people that run it, and there has been since shortly after the Civil War. It is proof beyond a reasonable doubt of those statements, if you wish to see non "speculative" evidence. It shows quite clearly that the government has been completely compromised by the Cabal (total control) since at least the 1860s.

I have given you a glimpse into easily verifiable facts about the beginning of the country that you can look into, and I have given you an extremely detailed report, made up completely of evidence that shows they owned the whole thing since the 1860s (I show explicitly that the Gilded Age never ended and indeed, only got worse and more hidden). That leaves out a couple decades in between, and I can easily fill in that gap and expand on the beginning substantially, but it at least points you in the right direction. The evidence that exists isn't "no proof" and "pure speculation." On the contrary, it's overwhelming without a smidge of speculation required, because it's all written into law, and official demographics, and other such period documents..

One more example, just read the Constitution. There are several pieces of Bankster fuckery in there, but the fifth amendment is the most obtuse offender. It lays explicit claim to all people as subjects to the US Govt that they can take control of at any time (completely subservient) for "national security" purposes. It further lays claim to ALL property as belonging to the Sovereignty (ultimate authority) of the Govt., which means it can take it from you at any time. But who can take it from you? Because a government can't actually do anything, a government can't be an "Ultimate Authority". It isn't a real entity, it is a legal fiction. Only people can do things, perform actions, subjugate people, take property. People can do these things in the name of the government, but it's still people, and the government just makes you believe their actions are "legal," which indeed they are because it's written into the Constitution. But the important question is again, who can do these things? The answer is, the Aristocrats (or, in reality, almost always the Cabal) that are in charge, the "voted in 'representatives'" who stay in charge through the system of laws and economic, social, and media driven coercions they created to ensure that is forever the case.

The most reasonable overview I have come across so far is The Clash of Two Americas Volume 1 by Matthew Ehret. There has been something like a deep state since almost day one, it was really a 5th column serving the interests of the British empire. But that's not the whole story. Two Americas, two competing visions, it wasn't like the cabal was the only one with the upper hand the whole time. Give it a read.