That's tough to answer, since it depends entirely on how the Trump administration chooses to go about it, if it indeed chooses to go down that disastrous road. Pompeo's threat to bring Iran to its knees with punishing economic sanctions clearly won't get the job done, especially since the Trump administration has just alienated its most important potential partners by withdrawing from the Iran nuclear deal. Good luck getting France, or the United Kingdom, or Germany, much less Russia or China, to join in a campaign of maximum economic pressure on Tehran after the Trump administration has walked away from a painstakingly negotiated multilateral deal that was working to achieve its only stated objective -- stopping Iran from developing a nuclear weapon.
Next-level steps could include supporting anti-regime groups like the Mujahadeen-e-Khalq (MEK), which was for many years on the US list of terrorist organizations. But its ability to win over influential supporters like John Bolton does not mean that the MEK has either the capacity or the support to overthrow the Iranian government.