An excerpt from one of former President Barack Obama's previously unpublished law school papers revealed he believed the American dream was to be like Donald Trump, although he called such a goal "unfounded optimism."

At age 29, Obama wrote a paper with friend Robert Fischer titled "Race and Rights Rhetoric" in his last year at Harvard Law School. An excerpt of the paper was published in a biography of Obama's early life, titled Rising Star: The Making of Barack Obama, Vice reported Friday.

Obama had written that the average American mindset can be summed up in one sentence: "I may not be Donald Trump now, but just you wait; if I don't make it, my children will."

He criticized such an idea, however, as the "unfounded optimism of the average American," arguing that this "continuing normative commitment to the ideals of individual freedom and mobility … may be summarily dismissed" as such optimism.

In 1991, Obama and Fischer argued that African Americans should shift towards the language of opportunity.

"Precisely because America is a racist society… we cannot realistically expect white America to make special concessions towards blacks over the long haul," Obama and Fischer wrote.

Obama has been a staunch critic of Trump since the start of his 2016 presidential campaign and has continued to make indirect digs at Trump since leaving the White House.

UPDATE: 2:49 P.M.: The original version of this article did not include that Obama called the American idea of being Donald Trump the "unfounded optimism of the average American."