The Framers created the Senate as a majority-rule institution. The filibuster was invented much later for the primary purpose of preserving white supremacy. McConnell wants to keep it because it lets a predominantly white, conservative minority impose its will on the majority.
Good Q. Complicated answer because the position of Senate leader didn’t exist until 20th century and didn’t have any real power til LBJ. Tl;dr is, the modern Senate gives leaders many tools of indirect control & tactics to block others from offering bills.
This is true, too. At the end of the day the power of Senate leaders is based on a series of overlapping norms and learned behaviors, and carrots and sticks - not formal powers enshrined in Senate rules.
