RCV lacks the quality of “precinct summability” which means that all ballots have to be centrally tabulated. This is a serious security issue because there is a

RCV lacks the quality of “precinct summability” which means that all ballots have to be centrally tabulated. This is a serious security issue because there is a single point of failure for an attacker to undermine auditing measures. Here in Oregon, for example, state law requires that tabulation for a county's precincts must be done by the county clerk using nothing more than the information on the ballots cast in their county. This ensures that no one centralized authority can be compromised to throw a state-wide election. It also means there's no legal way to tally RCV elections in, for example, cities that span multiple counties or in state legislative districts that span multiple counties.