P6,
No. with or without Article 1 Section 5 the 17th amendment would have been enough. Now if the amendment process had not been included in the costitution then the 17th would have been impossible. But Art 1 Sec 5 didn't have anything to do with the 17th.

But I'm speakfrom a constitutiona aspect. Are you trying to say that politically Art 1 Sec 5 softened things up to make the 17th possible? If that's what you were meaning then I would still disagree but I'd be more willing to consider it as plausible than if you're meaning is strictly constitutional.