The best impermeable rock (ie. granite) formations for this purpose are in the eastern US. Congress excluded them from consideration as sites when they mandated the selection of Yucca Mountain as the sole site in 1987.
Exactly: the waste problem is a political one, not an engineering problem.
But it's moot anyway, because the US doesn't reprocess it's waste. So today's nuclear waste is a source of fuel later and it's be a waste to bury it before reprocessing anyway.