I found this exchange between William Voegeli of the Claremont Institute and Gerald L. Houseman, representing a group calling itself "Taxpayers Against Extremism" (TAX), amusing. The only "extremism" Houseman wishes to deprive of tax-exempt status is that supported by conservative-leaning foundations.
The only Gerald L. Houseman I can find through a Google search is a much published professor at Eastern Washington University in Spokane, who worked as a Democratic precinct officer in the last election, and who is likely the same guy who lost an election in 1996 to U.S. Representative Mark Souder (R-IN). In other words, he’s a not atypical member of the Democratic Left. As Voegeli points out, when Dennis Kucinich is President, we’d better be worried.