An unsigned 1999 memo to Hillary Clinton warned of the Vatican's "hardline" and "extreme" positions, ahead of a visit by the then-first lady to the Holy See.
The memo was contained in a trove of 4,000 pages of documents released Friday by the National Archives.
The memo repeatedly made the point that the Vatican and Pope John Paul II were outspoken in their opposition to abortion and contraception.
"You do not need to raise those issues where the Administration and the Vatican strongly differ; if they come up, you should just agree to disagree," the memo advised. "In addition to adolescent sexuality and reproductive rights, these issues include abortion, artificial contraception and sterilization, and individual reproductive rights - basically, anything other than marital couples practicing periodic sexual abstinence."
The memo continued: "Under the Church's position that every act of intercourse should hold the possibility of conception, only periodic abstinence is acceptable as a family planning method. The Church opposes even condom usage for protection from HIV/AIDS. This position is more extreme than that of conservative U.S. activists ..."
Hitting the point once more, the memo said: "The Vatican's hardline positions are not followed by many clerics and most laity, nor are they in the religious mainstream."
It's not the first time signs of tension between the Vatican and the Clintons have emerged. On the way to Pope John Paul II's funeral in 2005, former President Bill Clinton said he "may have a mixed legacy."