Most of the book is about the history of the SWAT Team concept, how it developed and how it mutated to the point where today cities as small as 25,000 have them. It also details the way in the SWAT concept has changed the mindset of police, to the point that SWAT teams are used today for routine police practices like serving warrents and even to enforce regulatory compliance in certain areas, and how this threatens everybody.
Perhaps the author, as a fellow at the Libertarin-leaning Cato Institute, has an exaggerated sense of his, and our, rights under the 3rd and 4th Amendments. Still, we see stories every day of police excesses and the lack of accountability that should scare the bejesus out of us. By the way, it might not seem that the routine police abuses the author describes are violations of the 3rd Amendment against the quartering of troops in private homes, but he provides an historical context of the 3rd Amendment in which it makes sense to describe them as such.
The blame for the gradual militarization of the police over the years is bipartisan. Nixon deserves a good deal of criticism because of his cynical initialization of the so-called war on drugs and his dehumanization of all drug users as well as dealers. Reagan merits some severe censure for his upping the ante of the dehumanizing rhetoric as well as his policies, such as his approving the involvement, at the urging of VP Bush and his aides, of the CIA and the Military in the war on drugs. But every President since has bought into the concept of federalizing the war on drugs and the militarization of the police.
Obama and Biden both come in for a lot of criticism. Biden, as a Senator, was a big advocate of the federal war on drugs and of the transfer of military equipment to the nation's police forces. G.W. Bush actually stopped the funding of that program but, unfortunately not because he had any principled opposition to it, but only because the military needed every cent in its budget for Iraq and Afghanistan. Obama campaigned on the promise that he would restore the funding, and he did . He not only restored the funding, he expanded it significantly (quadrupled I believe) and the nation's police are more militarized than ever.
The Supreme Court decisions which have allowed this diminution of individual rights and accretion of police powers has, by and large, been bipartisan too. William Brennen is a notable exception (as was Sam Ervin in the Senate back in the day). Regarding the so-called originalists on the court, Balko, after giving us a history lesson about the origins of the 3rd and 4th Amendments, notes that they are originalists...until they're not.
The author makes the point early on that this is not an anti-police book, and I think that is clear. It is not just a litany of police abuses, although they do come up often enough that you should know, first, that your home is no longer your castle. Second, you should know that when your castle is invaded because the police got the address wrong, nobody is going to be held accountable. Third, your dog(s) will probably die. For some reason, police like to shoot dogs. You'll probably have to replace your broken door at your own expense. In some locale, I don't recall where, police raids to the wrong address are so common that the police actually have a printed document to give the unfortunate home owner tips on where to go and who to call to get his/her door replaced.
If you are by chance wondering why so many doors are broken, good, that's an appropriate reaction.