Create logo for web-based non-profit with 20 million users

ProCon.org

ProCon.org is a web-based non-profit with 20,000,000 annual users. Our mission is: “Promoting critical thinking, education and informed citizenship by presenting controversial issues in a straightforward, non-partisan, primarily pro and con format.” Our diverse audience is composed of educators, students, major news media organizations, governments and the general public. Our website will give you a better understanding of what we do and how we do it: http://www.procon.org

The logo should immediately and clearly give the viewer a sense that
“ProCon” stands for “pros and cons” in order to build an
association between the logo and what we do. (For example, the logo
might convey the concept of opposition, debate, opposing views, etc.)
The logo should convey a sense of seriousness and gravitas consistent
with our status as a non-partisan, balanced, research-based,
educational and civic-oriented organization. We have no preference
whether the logo is a stylized version of our name, or is a separate
logo. If it is a separate logo please show how you believe our name
should appear and how it should be used with the logo. We do not want
a logo that is a variation of our existing logo.