Possible Clues:

• "When __ detected, a thousand are suspected": Thomas Paine
• Start of a Three Dog Night hit
• "--- the Loneliest Number"
• ''___ the loneliest number ...''
• 'When ___ detected, a thousand are suspected': Thomas Paine
• "___ the loneliest number . . ."
• '___ never enough'
• '-- the loneliest number'
• "___ the loneliest ..."
• '___ the loneliest number' (Three Dog Night lyric)