From Darryl Hart and John Muether’s 1997 article entitled “J. G. Machen and the Regulative Principle”:
Machen [in 1926] opposed Presbyterian support for Prohibition, however, not because he approved of drunkenness or preferred unpopularity. Rather he did so for important theological–even Reformed–reasons. In a statement defending his position (never published again because of the damage his friends believed it would have done) Machen argued that the church had no legitimate rationale for taking a side in this political question. Aside from the question of the relations between church and state, he believed that the church was bound by the Word of God and so all of its declarations and resolutions had to have clear Scriptural warrant. The Bible did not, however, provide support for Prohibition. It taught the idea of temperance, that is, moderate consumption of alcohol and the other good things of God’s creation. This meant that Scripture forbade inebriation. But even here the Bible did not give directions to government officials for abolishing drunkenness. Should this be a matter for the federal government to regulate or should states and local governments? Was legislation the best way to shape public sentiment or was an educational program more effective? Was regulation of private citizens’ behavior even a proper concern of the state? The Bible did not answer these and various other questions. So, Machen concluded, the church had no business meddling in the politics of Prohibition or any other matter where Scripture did not speak.