Interest groups affect political decision-making by influencing public policy and government actions through lobbying, advocacy, and mobilizing members. These groups represent diverse interests, including business, labor, environmental, and social issues, working to sway legislators and shape laws that align with their agendas. By providing information, funding, and organizing grassroots campaigns, interest groups can impact electoral outcomes and enhance their political power. However, their influence can also raise concerns about potential corruption and the disproportionate representation of wealthy interests in the political process.