And STV works well for Ireland, and I think would also work well for state-level elections in the US. The only thing is that it doesn't scale up super well, and

And STV works well for Ireland, and I think would also work well for state-level elections in the US. The only thing is that it doesn't scale up super well, and might not work quite so well for congressional elections, though IRV might work if they wanted to keep single-member districts, even if it's less proportional than proper multi-member STV. Regardless, it'd be an improvement on FPTP and reduce the spoiler factor.