• Co-chair of Win Without War
• Executive Director of Women's Action for New Directions
• Consultant for the National Democratic Institute
• Served as the President of the League of Women Voters of Massachusetts

Susan Shaer is the co-chair of Win Without War (WWW), which describes itself as a "coalition of national organizations representing broad constituencies that aim to keep America safe by advocating that international cooperation and enforceable international law provide the greatest security for the United States and the world." Opposing what it calls "the militarization of our foreign policy," WWW condemns "the doctrine of unilateral military pre-emption." The organization purports to offer "a mainstream, patriotic voice for engaging opinion makers, activating concerned citizens, and communicating effectively to the media." In practice, WWW is an anti-war coalition of leftwing groups that oppose Republican office-holders and seek to replace them with leftwing alternatives. It wishes to make American foreign policy fully accountable to world opinion and multi-national consent. What it characterizes as "activating concerned citizens" often amounts to exhorting groups and individuals to participate in demonstrations that portray America as a terrorist nation and the world's foremost human rights violator.

In addition to her work for WWW, Shaer, an arms control advocate, has chaired Project Abolition and the National Coalition for Peace and Justice. She also co-founded the progressive tax-lobbying group TEAM (Tax Equity Alliance for Massachusetts), served as president of the League of Women Voters (LWV) of Massachusetts, and sat on the directors' board of LWV's national chapter. Shaer currently serves as the executive director of Women's Action for New Directions (WAND), which is a coalition member of WWW. Though WWW's stated policy is that its member organizations cannot be politically partisan, WAND, through its Political Action Committee, endorses Democratic and Progressive female candidates exclusively. One of WAND's 2004 endorsees was Betty Castor, the former president of the University of South Florida (USF) who refused to fire from her school's faculty the terrorist Sami al-Arian. WAND is a founding member of the United for Peace and Justice (UFPJ) coalition.

Shaer is a consultant for the National Democratic Institute, which "works with Democrats in every region of the world to build political and civic organizations, safeguard elections, and promote citizen participation, openness and accountability in government." She also serves on the Advisory Board of Teen Voices magazine. Her husband is Democratic Massachusetts state representative Jim Marzilli.