The problem behind the scenes here is the 17th amendment to the Constitution which takes the power away from the state government to appoint a state senator and gives it to the people to vote every six years. While the term was still 6 years, the state legislature could always vote to recall them ( a process much easier than getting the population to do the same). Under this system the senators were always accountable to someone and the states had some say in federal issues.
Senators could not be recalled before the 17th Amendment either.
At some state ratification conventions antifederalists argued that the Constitution should be amended to allow recall of Senators but it wasn't.