play a role in a computer-based approach. Alternatively, redistricting algorithms can be used to find gerrymandering. An algorithm can compare proposed districts to a sample of other potential redistricting plans to determine to what extent the proposed districts are outliers. If proposed districts have more extreme features than most of the sample, the proposed plans are likely gerrymanders. This kind of analysis has played prominent roles in partisan gerrymandering litigation. Many redistricting algorithms have been developed with varying results and several programs are capable of satisfying all of the redistricting criteria. No U.S. state has adopted a redistricting algorithm. Although, some states have introduced proposals to consider redistricting algorithms. Alternative voting systems The predominant voting system in the United States is a first-past-the-post system that uses single-member districts. Various alternative district-based voting systems that do not rely on redistricting, or rely on redistricting minimally, have been proposed that may mitigate against the ability to gerrymander. These systems typically involve a form of at-large elections or multimember districts. Examples of such systems include the single-transferable vote, cumulative voting, and limited voting. Proportional voting systems, such as those used in all but three European states, would bypass the problem altogether. In these systems, the party that gets, for example, 30 percent of the votes gets roughly 30 percent of the seats in the legislature. Although it is common for European states to have more than two parties, a sufficiently high election threshold can limit the number of parties elected. Some proportional voting systems have no districts or larger multimember districts and may break the strong constituency link, a cornerstone of current American politics, by eliminating the dependency of individual representatives on a concrete electorate. However, systems like mixed-member proportional representation keep local single-member constituencies but balance their results with nationally elected or regionally-elected representatives to reach party proportionality. Effects Democracy A 2020 study found that gerrymandering "impedes numerous party functions at both the congressional and state house levels. Candidates are less likely to contest districts when their party is disadvantaged by a districting plan. Candidates that do choose to run are more likely to have weak resumes. Donors are less willing to contribute money. And ordinary voters are less apt to support the targeted party. These results suggest that gerrymandering has long‐term effects on the health of the democratic process beyond simply costing or gaining parties seats in the legislature." Gerrymandering and