This study was primarily a multiple-case study that incorporated descriptive statistical analysis to examine the contributions that three niche institutions play in the diverse democracy of the U.S. A "niche institution" is a college or university whose role in U.S. higher education is to meet the needs of a specific group and whose resources are influenced by perceptions of the institution's relevance by specific populations and interest groups, state and federal governments, and others who are in a position to influence the allocation of resources. Findings for each case study are discussed in detail by institution, and then a comparison of findings across the three institutions were categorized by four themes: 1) niche institutions' role in the higher education marketplace, 2) niche institutions as social selves, 3) community engagement and outreach, and 4) niche institutions' potential for promoting substantive citizenship in a diverse democracy. Implications for institutional leaders, policymakers, and scholars are also discussed. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]