Our thoroughly educated and distinguished founding fathers spent more time on the careful construction of our Senate than on any other topic. They wanted it to be populated with the highest and best humanity had to offer. So, they concluded, by a vote of 10 to 0, that such a Senate could best be achieved by assigning State legislatures the chore of selecting them; not the public at large who were already given the House of Representatives.
They would no doubt be biased in this regard, but if the founders could be resurrected long enough to survey how we managed the well-considered legacy they gave us in 1787, and how Amendment Seventeen (A17) impacted that legacy, they would be horrified. "What were you thinking?" they would likely ask as they discovered our slowly deteriorating condition, "We intended for you to have a republic, not the popular democratic spectacle of turbulence and contention demonstrated by the ancient record."
Now that we've had more than a hundred years of experience with (A17) and its revised, 1913 formula for popular Senate elections, we should be able to parse the available evidence on the before and after 1913, were we interested enough to do so, in order to determine whether or not A17 was a net good thing for us, or a bad thing; whether or not it was a Blessing for the United States, or a Curse.