Stefan Molyneux claimed that the US state has become more tyrannical and violent because it's running out of money to bribe their constituents. While this certainly adds a level of desperation the primary cause is an accelerating cycle of propaganda and failure. The State is fundamentally trapped by the expectations it creates and every time it expands it's power and expense to escape this trap it makes this worse. One of the problems is that the State's agents are highly propagandised themselves and therefore cannot adjust policies even to benefit the state.
The drug war is a great example of the propaganda/failure cycle. It started with a flawed idea of removing drugs from America. Naturally this failed. In response to any failure the person or group who fails has four options. Firstly they could state that the original concept was fundamentally flawed and unachievable. Secondly they could state that while the concept is sound, they are not competent to execute it. Thirdly they could claim that they could achieve it but were not allowed to do the things neccesary to do so. Fourthly they could claim that the policy suceeded, possibly by redefining "success". A propaganda/failure cycle occurs when the first two options are extremely undesirable in career and pyscological tersm for those participating and the fourth is not credible. The drug war is a prime, but by no means only, example of this in government.
As failed results for a policy accumulate the part of the state held responsible for it has a problem. This includes not just cops and civil servants, but senior policy makers and politicians. They must maintain the belief that the policy is worthwhile and best achieved by keeping the current personel largely intact. Of course the occasional sacrifice, even a high ranking one, can be made. One or two can retire to spend more time with their families, the interests of the families of course being irrelevant. However if the participants are to retain their careers, their prestige and most importantly their self-belief then the main body of them must continue doing the jobs they're doing. Therefore they insist that they must be less restricted if they are to achieve their goals. The two main forms of this are requests for more resources and for greater ability to violate traditional liberties.
If this approach results in something that can credibly be called a "success", at least at a minimal level, then further attacks on liberty, fraternity and prosperity are unnecessary. That doesn't mean they won't happen, but they will certainly be less rapid and may be abandoned in the face of determined opposition. If the project, like the drug war, is fundamentally flawed and incapable of any but small and transitory sucesses then each expansion of resources and powers must be followed by another. Not to do so is impossible because the people making the decisions have a combination of interest and propagand-created belief in the program that makes it impossible to abandon it. There are occasional exceptions to this for instance Law Enforcement Against Prohibition, but the vast majority of the people in the apparatus will be effectively rock solid on continuing.
To understand why this is so consider that they are the prime recipients of State propaganda for the project. Obviously those who believe most in the project will be more likely to be recruited for it. After recruitment their leaders will have an interest in continuing the propaganda so as to get the best motivation and results. This is true even if adequate results are impossible to achieve since the leader of each section wants to have his team shine compared to other teams. Those who are not effectively propagandised will tend to leave the project as it's failure becomes more and more evident. Those that remain have invested more and more time, knowledge and esteem (including self-esteem) in the project and lose it if failure is ever acknowledged. Therefore they have an interest in never admitting defeat and that interest is abetted by their bosses.
Each time the participants attempt to increase the money and power available to them they must propagandise the people who determine whether or not they are allowed to do so. This is to some extent the general public, to some extent business leaders, special interests, politicians, foreign governments and anyone else whose support or at least non-opposition could prevent the increase. A certain power balance must be achieved to actually advance, and since the policy is fundamentally flawed it cannot deliver net benefits. Therefore some must be deceptively convinced they gain by the policy and those who lose must be propagandised to ignore their costs. The resultant propaganda is a trap. The relevant parts of the State cannot be "depropagandise" these people, or even attempt to do so, without a backlash of anger and resentment. They effectively become part of people held responsible for the policy, since they supported it. To see it end would implicate them in the abuses inflicted for it which were justified "pragmatically". This would make the supporters even since once the ends that justified the means are gone, there is just the evil means. Therefore they form part of the reason that going back on the policy is "politically impossible". That is to say no sufficiently powerful combination of political forces exists opposed to the policy. Too many people have too much to lose from it's ending.
Not only that but the project must continually seek to expand it's size, power and abusiveness. Since the excuse for failure is insufficient size, power and abusiveness in the inevitable absence of sucess a vote not to expand these is effectively a vote to end the project. If the statement is made "We must allow (warrantless searches/confiscation without trial/abusive detention/etc) if we want to end (insert problem)." then a refusal is effectively saying it's not a gaol worth pursuing. If the goal is not worth pursuing then the conclusion will be reached that obviously the current costs in liberties and money aren't worth it either. Since the entire aim is to avoid that conclusion this is unacceptable and the people held responsible for the project will do anything to avoid it. Thus the cycle ends only when the expense and abuses are so egregous a fundamental political realignment, possibly a revolution occurs. This stage is fast approaching in the USA.
Lastly the reason I don't believe that bankruptcy and subsequent ending of goodies for the people are the reason for the most recent new tyrannies. The powers that be are fully aware that they don't have the strength to suppress the parasite classes. There are simply too many people who get goodies from the current system to jail them all or even a large enough part of them to intimidate the others. Naturally both wings of the Demopublican party will be bribed but there comes a point at which even the most extravagent campaign donations and ludicrously biased coverage won't make up for the votes lost from no longer divvying up the loot. Therefore it's politically impossible to pursue this as well. Indeed attempting to use these tactics against the parasite class will destroy their support for it's use against others massively eroding the power of the State.