One of the biggest "checks" in government is a fair and open election.
The reason for the 17th Amendment was to put an end to corruption.
And yet, the 17th amendment did the exact opposite because it eliminated the check the States have on the Federal government and allowed special interest groups to directly control Senators.
Did you ever stop to think that the Founders set it up a certain way for a reason? Maybe instead of rushing to assume that your way is better, you should stop and ask "Why was it set up the way it was?"
The States now have little recourse against the Federal government. Which is why immediately after the 17th amendment was passed, the Federal government began spending like crazy and installing big government programs at the costs of the tax payers.
See our system works when there is a balance of power between the people, Feds, and States. When one of the legs is weakened and power taken for the others, we only have two legs of a stool to stand on. That eventually becomes one leg. A three way division of power works, a two way division rarely works. It quickly becomes one. That's one of the reasons why the Roman Triumvirates worked so well and the second one of the three was long longer in power the Republic went to Civil war.
It's ironic, that by empowering individuals in the short term, the progressives have successfully removed the obstacles they need to oppress them.