Possible Clues:

• 'The power to make it better' organization
• Org. with over 35 million members
• Group with a powerful D.C. lobby
• Group that offers free memberships to spouses
• Org. with more than 35 million members
• Over-50 organization
• Org. with a huge-circulation magazine
• Group that publishes the two most widely circulated magazines in the U.S.
• "The power to make it better" org.
• Highest-circ. US magazine