GENEVA—Iran and world powers neared a crucial compromise Friday on a late roadblock to a deal to curb Tehran’s nuclear program, according to Western and Iranian diplomats taking part in the negotiations. A compromise on that issue—Iran’s demand that it be explicitly allowed to keep some domestic uranium enrichment capacity—could lend momentum to the push for an agreement and at least a temporary reprieve from a decadelong standoff over Tehran’s program and elevated fears of war over it, according to these officials. French Foreign Minister Laurent Fabius arrived in Geneva Saturday morning to join the Iranian nuclear talks, saying he wanted to see a “solid” deal reached. Mr. Fabius played a key role in the last round of Iranian negotiations two weeks ago, saying publicly the draft agreement under discussion was not tough enough on several key points. Iranian officials have since blamed France for scuppering a deal. Speaking […]