On Monday the Supreme Court issued another ruling that limits the practical effectiveness of constitutional protections afforded to those accused of committing crimes. Commentary can be found in many places, but I'm partial to Scott Lemieux's witty reparte on the subject.
I don't think it's a coincidence that much of the pro-defendant case law happened to take place during the Civil Rights era. The legal-political project of the Warren Court was, largely, to acknowledge that local government officials tended to put their thumb on the scales in favor of a franchised white majority, and that the federal government should act as a counterweight on the side of the disenfranchised. So we got case after case that overturned the actions of local government officials, who are now presumed to have a level of racial bias that was previously ignored or considered morally/politically/socially acceptable. Forcing the '60s era local police to adopt bright-line rules surrounding the accused's rights to remain silent, discuss their case with an attorney, or not to be physically assaulted while in police custody is a way of primarily exerting control over the actions of (mostly white) police forces and prosecutors as they interact with (mostly nonwhite) potential defendants.
Thus we should not be surprised that as the level of racial inequality recedes, courts begin to grant more and more deference to the government in criminal matters. This is not to say that racism does not exist, but objectively speaking the level of animosity today is substantially lower than it was in the 1950s or 1960s. It will be difficult to maintain political support for rulings that protect the accused as racial bias continues to recede.