If the United States bombs an underground uranium enrichment facility in Iran or kills the country’s supreme leader, it could kick off a more dangerous and unpredictable phase in the war.

Just ask Jimmy Carter, whose White House term was forever framed by the unsuccessful attempt to rescue hostages held by Iran in 1979. That led to his defeat in 1980 by Ronald Reagan. President Donald Trump no doubt is aware of history – and perhaps irony as well – as events in Iran are again front and center at a pivotal moment early in his second stint in the White House.