No he didn’t turn from organized religion he just severed his membership with the SBC. In fact he is highly involved in a different Baptist church of a different association. Here’s a quick snip from his Wiki write up.
In 2000, Carter severed his membership with the
Southern Baptist Convention, saying the group's doctrines did not align with his Christian beliefs. In April 2006, Carter, former President Bill Clinton, and
Mercer University President Bill Underwood initiated the
New Baptist Covenant. The broadly inclusive movement seeks to unite
Baptists of all races, cultures and convention affiliations. Eighteen Baptist leaders representing more than 20 million Baptists across North America backed the group as an alternative to the
Southern Baptist Convention. The group held its first meeting in Atlanta, January 30 through February 1, 2008.
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