At Dr. Finley’s school, I was more fully instructed in those principles by means of the Westminster catechism. I retained them without any affection for them until about the year 1780. I then read for the first time Fletcher’s controversy with the Calvinists, in favor of the universality of the atonement. This prepared my mind to admit the doctrine of universal salvation, which was then preached in our city by the Rev. Mr. Winchester. It embraced and reconciled my ancient Calvinistical and my newly adopted Arminian principles. From that time I have never doubted upon the subject of the salvation of all men. My conviction of the truth of this doctrine was derived from reading the works of Stonehouse, Seigvolk, White, Chauncey and Winchester, and afterwards from an attentive perusal of the Scriptures. I always admitted with each of those authors future punishment, and of long duration.Rush listed most of the "big names" who influenced the universalism of the American Founding, but left one big one out: John Murray.
Today, George Sarris operates in that tradition. He has a book out on the matter entitled "Heaven's Doors: Wider Than You Ever Believed!" Theologians come to the universalist conclusion by using a combination of reason and revelation. What's distinguished about the more traditional universalism is the extent to which it takes the Bible seriously and seeks to justify its claims with biblical texts. We see this in Rush's above quotation.
Likewise, Sarris both believes in the inerrancy of scripture (in its original languages) and is a convinced universalist. And he can answer every single claim that is brought against him.
Something else that distinguishes the classical universalists is their belief in the seriousness of future punishment. The idea is there is a future state of rewards and punishments. And for the unsaved, they may be punished for ages before they are restored.
See the clip of the interview below with Eric Metaxas, who seems to have a great deal of respect for Sarris and his position. Listen till the end, whereas Sarris is a convinced universalist, Metaxas is hopeful that it is true. He even says he thinks all Christians hope this is true. I suspect most of them do. The decent ones. The ones who don't -- Pastors Sam Anderson, Fred Phelps -- make the religion seem like something not worth believing in. (In my opinion.)