The US would have to start relaxing the Iran sanctions as a show of good faith like they did last time.
Instead they are sending aircraft to the region to threaten Iran.
No one in their right mind would do a ground invasion of Iran. It is mountainous like heck. But the US went into Afghanistan too so who knows. I do know invading Iran was part of the US plan as proposed by the PNAC two decades ago. Iraq was supposed to be used as the launchpad to do it. First the US was supposed to invade Iraq. And then they were supposed to invade Iran and North Korea. But now North Korea has nukes, and I doubt an US invasion of Iran would not be accompanied by military aid from Russia and China. It won't be like the Iraq invasion.