Members of the US House were originally and still are elected to represent the people and so it was written into the Constitution that House members would be elected by a Popular Vote.
Members if the US Senate were originally appointed by a majority vote in state legislatures to represent states. In 1913, the 17th Amendment took this power away from state legislatures and gave it over to a Popular Vote.
Therefore, the people are represented by the House of Representatives and the US Senate. A US Senator is some sort of ‘Uber Representative’ of the people.
Why there needs to be a US Senate after the 17th Amendment is an interesting question. The US Senate no longer represents states and its members hardly represent individuals. Hence, they are prime targets for capture and control by financial interests which is what exists today.
What happened in the aftermath of the 17th Amendment is that State legislatures ceased to have any role in the affairs of the federal government and all power amassed in Washington DC.
To drive the point home, think what would happen if a similar Constitutional Amendment was passed to abolish the Electoral College. What would be the fallout? The fallout would be that New York and California would decide who is the US President. All voter power would leave less populous states and amass to NY and California.
The above should give you an idea of why the States are like doormats to the federal government.
1913? I Wonder who was behind it and why?