But you could have the least worst of the three worst evils. Which would make it the best of the three worst. Or the lesser of three evils. See, you have worse, worst, and worser...so the least worst would be the worse one, to say the least. But I dunno what's worse, being the least of the worst or the worst of the least. However, the least of the worst is pretty mediocre when you think about it...like liverwurst without mustard and onions--that would be liverworst or liverworse, at the very best. Not the least of which would be the absence of rye bread, which would make it liverworstest. But I dunno which is liverworster, do you? Which is the least worse of the liverworst..sans onions, sans mustard, or sans rye bread? So, you see, least qualifying worst is, at worst, pretty simple, when you take a look at it in application at least.
Now, if you'd wanna get into the declension of least, leaster, and leastest...well, that's the worst least discussion you can into, believe me.