[The Grammarian]

Al Sharpton is an ordained Pentecostal minister. If he is elected, he would be the first clergyman to become president.

The author didn't do their homework. James Garfield was the first clergyman to become president, in 1880. (He was a minister in the Christian Church denomination.)

[Verginius Rufus]

Was Garfield actually a minister? William DeGregorio in The Complete Book of U.S. Presidents says that "he was for a time a lay preacher" in the Disciples of Christ church, and that "he considered taking up the ministry but decided to teach instead." (He taught classical languages for a while and then became a lawyer.)