The Biden administration is trying to get a deal with Iran and they want to return to the deal that Obama made and Trump canceled. This allows Iran to enrich uranium up to 4% but Biden is planning to expand that to 20%. Enriching uranium is not linear. Once you reach 20% you are 90% of the way to 93% which is what is needed for a bomb. In addition he is removing sanctions and paying Iran to store their enriched uranium in Russia with the understanding that if the US backs out on any part of the deal the Russians could send the uranium back to Iran. I have long maintained that Iran could have made a bomb many years ago but just use the threat to bargain with and it seems to be working well with Biden.