I tend to agree with this. When an entity takes new power, they fight tooth and nail to keep it, regardless of whether it's "right" for them to have it or not. Bush II massively increased the power of the executive branch with terrorism and fear as an excuse, pushing it farther from a checks-and-balances system towards a checks-against-the-president system. Now that it's been established that the executive has greater power, does anyone think any upcoming president will sit down and say, "welp, time to give some of this up and bring it back to how things used to be!" I don't think so.
Same with civil liberties taken by police and other enforcement. The attitude some (not all, or even the majority of) officers seem to have is the attitude of control and being the boss, not serving and protecting. (Like this article--on what imaginable grounds did the officer think he could arrest a citizen for taking film from within their own house if not because "I don't like being on film, so I'm going to show this person who's boss by arresting them"). When it becomes a case of maintaining some sort of imagined and idealized "order" instead of enforcing specific law, our liberties are eroded; and when we just lay back and take it, they probably aren't coming back, because those erosions then eventually become law as people and enforcers get used to the idea.
There are of course cases where things have been turned around for the better, like civil rights, suffrage, etc. But this more modern trend of slow, steady, and insidious erosion of rights in the name of protecting us is that much more dangerous because we've become convinced we need the protection.
And when the enforcers have the big guns, the ability to detain or throw anyone in prison for almost anything, and a staggeringly complex body of law that requires a small fortune to defend against, things aren't so easy to change anymore. I'm not talking black-helicopter conspiracy theories or anything here, just a general sadness to see us giving up so much of what makes real life free and enjoyable for the illusion of safety from child rapists and terrorists.