Twoparty

Twoparty, or a two-party system, is a political arrangement in which two major parties hold the vast majority of political power across government institutions, while smaller parties compete but win few seats or offices. In such systems, electoral rules and historical development tend to concentrate competition between the two dominant parties, shaping policy choices and governance.

Key characteristics include regular competition between the two leading parties for legislative seats and executive offices, a predominance of winner-take-all or single-member district rules, and a tendency toward stable, continuous governance. Voters often tailor their support to one of the two main parties to avoid “wasting” their ballots, a phenomenon known as strategic or tactical voting. These conditions can produce policy continuity and clearer accountability, but may also limit ideological diversity and reinforce partisan polarization.

Consequences and criticisms of twoparty systems vary by country and context. Proponents argue that two dominant parties simplify choices for voters, enable decisive governance, and foster bipartisan cooperation on core issues. Critics contend that such systems marginalize smaller parties, reduce policy experimentation, crowd out minority viewpoints, and contribute to adversarial or polarized politics. In some cases, regional or institutional factors (such as federalism or staggered elections) can create hybrid patterns that resemble a two-party dynamic in practice even when more parties exist.

Examples commonly cited include the United States, where the Democratic and Republican parties dominate national politics, and, in historical terms, other countries have experienced periods of two-party dominance in certain eras or at particular levels of government.