Should there be a new amendment to Constitution to make sure that only bona fide residents vote in elections?

I guess it all depends on your definition of Bona Fide. Lets consider the problems with what you propose. You live in Kentucky. Your job transfers you to Tennessee. You move and are no longer a resident of Kentucky, but haven't lived in Tennessee for a year when the next election occurs. Should you be deprived the right to vote in that circumstance? That's precisely the result of such a thing. Why should a work related move cause you to be disenfranchised for a year?

That link didn't have any info on the case. But if you're talking about federal elections then there's shouldn't be a state residency requirement anyway. I've also never heard of a non-citizen voting. Maybe it's happened, but it's extremely rare.

If you can register, you can vote once. The Court struck down that law because it would have denied the man's constitutional right to vote once.

What difference does it make. We're going to elect another douchebag anyway. The right people never get elected.