It may have started with Amendment XVII when Senators became directly elected. That was a marker for the start of a slide from the Senate’s representation of a State to its being a more direct representation of the people directly. It is a slide towards populism. It all sounds good. The current Senate is taking the idea to heart. See Orrin G. Hatch: Destroying the Senate — and our liberties. “Procedural changes impede the chamber’s traditional deliberative function”
“The Senate was designed to play a particular role in a carefully designed system of government that is based on two related ideas expressed in the Declaration of Independence: First, government exists to secure the unalienable rights of individuals; and second, government must be limited or it will, in fact, destroy these individual rights. Those limits include dividing power between the federal and state governments, separating federal power into three branches, and splitting the legislative branch into two very different houses.
“The Constitution lets the House and Senate set their own rules, and throughout the nation’s history these forms have developed consistent with each body’s function. The House’s function is action, and its form has been majority rule. The Senate’s function is deliberation and its form has given all senators, even those in the minority, a significant role.
“Throughout its history, all senators have had two essential opportunities to participate: the right to offer amendments to legislation and the right to unlimited debate. The current Senate majority has attacked both of these rights relentlessly.”
The war on what the country was is not only being engaged in the executive. It is not only a contemporary phenomena. It is one thing to try for something better but the persistent efforts to demolish what works to replace it with what has a serious record of failure, with pipe-dreams and ideological fixations, is not one for peace and prosperity.