There’s a tentative international nuclear agreement with Iran. But there are still plenty of critics of the President Barack Obama’s foreign policy with the Middle Eastern country.

Republican U.S. Senator Tom Cotton wrote a letter to Iranian leadership, saying a nuclear deal could be unraveled by the next president. Cotton defended the letter, claiming:

    “We know so far that Susan Rice, the president's national security adviser, has already conceded that Iran will have a robust uranium enrichment capability. The president has said this bill will have a sunset, perhaps as little as 10 years (from now). Those two terms alone make this deal unacceptable."

PolitiFact rated the claim MOSTLY FALSE. Reporter Joshua Gillin said there’s simply no record of Susan Rice making that statement.

In a speech at a convention of the American-Israel Public Affairs Committee in March, Rice did say something similar. She said: “We cannot let a totally unachievable ideal stand in the way of a good deal. I know that some of you will be urging Congress to insist that Iran forego its domestic enrichment capacity entirely. But as desirable as that would be, it is neither realistic nor achievable."

In that statement, Rice never used the word “robust.” But she also makes clear a point that Gillin says gets to the heart of the matter.

“There’s no way you can go back to zero,” Gillin said. “There’s no way to make Iran unlearn what it has learned about processing uranium for nuclear reactors.”

Experts agree it’s nearly impossible to return Iran’s enrichment capability to zero. Experts also say there are too many unknowns to gauge Iran’s enrichment capability and that the term "robust" is too subjective. Because of those facts, PolitiFact rated the claim MOSTLY FALSE.

SOURCES: SUSAN RICE ON IRAN'S NUCLEAR DEAL