Why I didn't sign the Manhattan declaration

Challies says he agrees with John MacArthur:

John MacArthur offers this explanation as to why he will not sign. "It assumes from the start that all signatories are fellow Christians whose only differences have to do with the fact that they represent distinct 'communities.' Points of disagreement are tacitly acknowledged but are described as 'historic lines of ecclesial differences' rather than fundamental conflicts of doctrine and conviction with regard to the gospel and the question of which teachings are essential to authentic Christianity. … [It would] relegate the very essence of gospel truth to the level of a secondary issue. That is the wrong way—perhaps the very worst way—for evangelicals to address the moral and political crises of our time.