Public interest groups exert significant influence on legislation by advocating for specific issues and mobilizing grassroots support. These groups often conduct research, fund lobbying efforts, and engage in public campaigns to raise awareness and push for policy changes. By presenting expert testimonies and data, they seek to shape public opinion and persuade lawmakers to align legislation with their interests. The resulting dynamic showcases the interaction between democracy and advocacy, highlighting how organized citizens can impact decision-making processes at various governmental levels.