As mentioned in related threads, low-information Bernie Sanders is an excellent example why the ill-conceived 17th Amendment should never have been ratified.
More specifically, Sen. Sanders, along with many other low-information senators, including former Senators Clinton and Obama, have evidently never understood that the states have never delegated to the feds, expressly via the Constitution, the specific power to establish social spending programs like Social Security and Obamacare.
Eventually the voters would put state governments in the hands of Socialists, who would send Socialist Senators to Washington. Rendering the 17th. Amendment moot.