evidence: This past month has proven that Trump’s Iran policy is a dangerous failure. At the United Nations, Trump could not rally a single one of America’s closest allies to extend the UN arms embargo on Iran. Next, Trump tried to unilaterally reimpose UN sanctions on Iran, only to have virtually all the UN security council members unite to reject his gambit. Now there are reports that Iran has stockpiled 10 times as much enriched uranium as it had when President Barack Obama and I left office. [...] Five years ago, American-led diplomacy produced a deal that ensured it would take Iran at least a year to produce enough fissile material for one bomb. Now – because Trump let Iran off the hook from its obligations under the nuclear deal –Tehran’s "breakout time" is down to just a few months. And there is no serious diplomacy underway to reverse it. The bottom line is that Iran is closer to a nuclear bomb today than it was when Donald Trump took office. And Trump has no answer for that. Five years ago, even Russia and China stood with our European allies behind an American-led approach to Iran’s nuclear program.