By Amir Basiri

U.S. President Barack Obama has come under fire, especially from Capitol Hill, for his misguided nuclear agreement with Iran, which has provided a temporary but critical lifeline to a very dangerous regime. Two ballistic missile launches; rockets fired at ships in the Strait of Hormuz; ten American sailors detained and humiliated on camera -- all these highly provocative actions took place after Tehran signed the deal last year.

The recent decision made by Washington, to hand over seven Iranians convicted for violating international sanctions and U.S. embargoes, in return for five innocent American prisoners held in Iran, is also very troubling. It is hard not to see the failure inherent in U.S. policy vis-à-vis Iran.

Another decision by Washington, to lift crippling sanctions on Iran, handing over a whopping $1.7 billion in ransom money to Tehran, and further releasing $100 billion in frozen money, is equally worrying. It will succeed only in further emboldening an increasingly belligerent Iranian regime, creating even more tension and instability throughout the Middle East.

While it seems next to impossible in 2016, America should consider advocating regime change as the ultimate objective in Iran. Iran is without a doubt the world’s leading state sponsor of terrorism, and anything short of serious action will only facilitate Tehran’s investment in terrorism across the Middle East and beyond. Even Secretary of State John Kerry has acknowledged the possibility of money released by the U.S. eventually finding its way into the pockets of terrorist organizations.

The number one priority of any future U.S. administration has to be preventing Iran from obtaining nuclear weapons, by any means necessary. The North Korean experience highlights the consequences of American failure to act. Not only has Pyongyang obtained and tested nuclear weapons, reports indicate that it has done so with the close cooperation of Tehran.

The fact that Iran’s recent conduct has prompted anger and condemnation even from the Obama administration’s allies on Capitol Hill, known for their pacific and isolationist tendencies, is significant. Democrats in Congress have been vocal in opposing the decision to lift the sanctions on Iran. This should be a wake-up call for the White House, which ought now to reinstate the sanctions. Moreover, it should consider the expansion of these punitive measures to also target those countries doing business with Tehran.

A broad strategy focusing on regime change in Iran has to be formulated, with a number of tools at its disposal: Sanctions; pressure on the diplomatic front; covert operations; a fierce military presence in the Middle East that will regain the lost trust of regional allies; and, most importantly, understanding the role of dissident groups -- especially the People's Mojahedin Organization of Iran (PMOI) -- and providing support for their efforts to establish democracy and freedom in Iran.

It is high time America stopped coddling the extremist hardliners in Tehran while allowing the flow of billions of dollars into their coffers. The Obama administration has forfeited too much during its seven years in office, while receiving next to nothing in return from its Iranian negotiating partners. Obama’s legacy should not be riddled with mistakes and miscalculations left for the next U.S. administration to repair.

Basiri is an Iranian political and human rights activist and supporter of democratic regime change in Iran. Follow him on Twitter: @Amir_bas