Barton's problems began when a band of conservative Christian scholars, led by Warren Throckmorton and Michael Coulter at Grove City College in Pennsylvania, dissected his book The Jefferson Lies and exposed the many errors therein. The book's publisher, Thomas Nelson (the nation's largest Christian publisher), pulled the tome.

More recently, Chris Rodda, director of research for the Military Religious Freedom Foundation and a longtime thorn in Barton's side, produced research indicating that a Barton claim about armed schoolchildren during the Wild West period defending their teacher from a killer was in fact taken from a novel by Western writer Louie L'Amour.

Barton originally told the story to Glenn Beck. He still insists that it might be true and claims L'Amour said it was. But as Throckmorton points out, that's not how history is done.

 "If there really is a basis in fact here," wrote Throckmorton, "it is a fair question to ask: how much more did the story change from the original source to L'Amour's book? L'Amour doesn't claim to be an historian and doesn't say what details were based on the account he used or what he added to make an entertaining novel. Clearly the reason one does not do history this way is because the narrative can change dramatically from the first telling to the last."

Rodda also took aim at another Barton claim about guns: that during the founding period, there were rarely gun-related accidents. Barton claims he could find only two. Rodda consulted an archive of historical newspapers and tracked down numerous accounts of people being maimed and killed due to gun accidents during this era.(Just to be clear: Americans United doesn't take a stand on gun control. The point here is to underscore how sloppy Barton's research is.)

Will any of this make a difference? Well, thoughtful evangelicals have been challenged to look anew at Barton's influence, and some of them are doing that. Some of the hardest-hitting material about Barton has appeared in World magazine, a conservative Christian publication that Americans United rarely finds itself in accord with.

More satisfyingly, it appears that some political leaders are finally questioning the wisdom of being tied to Barton. Over the years, I've been amazed at Barton's ability to ingratiate himself with certain political figures. Despite having absolutely no credentials, he even served as an advisor when social studies standards were being rewritten in California and Texas.

This week Montana Gov. Steve Bullock announced that he would not attend a prayer breakfast where Barton was the featured speaker. Bullock is a Democrat, and LGBT groups in the state had urged him not to share a stage with Barton, whose views on LGBT issues are predictably extreme.

Barton's standing among professional historians has already hit bottom. Is this the beginning of the end of this political influence as well? We can only hope.