No need to mourn the Iran nuclear deal. When President Donald Trump pulled the plug on it, after months of warning that the flawed 2015 agreement needed to be ended or mended, he was just taking a defective agreement off life support.

In his speech announcing the renewal of nuclear sanctions on Iran that had been suspended under the deal, the president noted that at the heart of the nuclear agreement "was a giant fiction that a murderous regime desired only a peaceful nuclear energy program."

In fact, the controversial agreement was making things worse. It did a much better job in dismantling sanctions against Iran than it did in dismantling Tehran's nuclear infrastructure. None of the illicit facilities that the regime covertly built in violation of the Nuclear Nonproliferation Treaty were required to be permanently closed down under the deal.

By allowing Iran to retain its nuclear facilities and rewarding it for cheating, the agreement in effect legitimized Iran as a threshold nuclear state.

Iran also was granted a better deal on uranium enrichment than Washington offered to its own allies. South Korea, Taiwan and the United Arab Emirates were denied uranium enrichment arrangements.

Incredibly, the Obama administration approved enrichment capabilities for Iran that the Ford administration had denied to Iran when it was a U.S. ally, before the 1979 revolution.

Moreover, the risky agreement gave Tehran massive sanctions relief upfront, while only requiring it to make temporary and easily reversible concessions that would delay, but not halt its nuclear ambitions.

Key restrictions on uranium enrichment would have been lifted after 10 to 15 years under the deal. Tehran then would have been free to ramp up its enrichment program to an industrial scale and build up its stockpile of enriched uranium, enabling it to make a final sprint to a nuclear breakout.

This is why the president warned: "The Iran deal is defective at its core. If we do nothing, we know exactly what will happen. In just a short period of time, the world's leading state sponsor of terror will be on the cusp of acquiring the world's most dangerous weapons."

Contrary to the promises of the Obama administration, the nuclear deal did not moderate Iran's hostile foreign policy. In fact, Tehran stepped up its malign activities in the Middle East since 2015, and the nuclear agreement has made a bad situation worse by boosting Iran's dictatorship in the economic, military and geopolitical spheres.

President Trump also warned that: "If the regime continues its nuclear aspirations, it will have bigger problems than it has ever had before."

But he was careful to distinguish between the regime and "the long-suffering people of Iran" whom he assured: "The people of America stand with you."

This implicit call for regime change was balanced with a willingness to negotiate a new deal with Iran. He ended on a hopeful note after acknowledging that Iran's leaders had ruled out new nuclear negotiations: "But the fact is they are going to want to make a new and lasting deal, one that benefits all of Iran and the Iranian people. When they do, I am ready, willing and able."

This was precisely the right message to send. Iran's repressive rulers know that they stand on shaky ground. They are increasingly unpopular and were targeted by a wave of public protests in January in which they were denounced for their mismanagement of Iran's faltering economy, widespread corruption and squandering Iran's resources by meddling in Syria, Lebanon and Gaza.

Trump's triggering of economic sanctions now confronts Iran's regime with a dilemma: if it clings to its nuclear ambitions it risks provoking a renewed popular rebellion against its misplaced priorities, in addition to a possible military confrontation with the United States.

The diplomatic ball is now in Tehran's court.

But Trump has changed the nature of the game. He is trying to work with the Iranian people to leverage their growing disaffection with their own rulers.

Iran's rulers can make the situation worse by threatening to crank up their nuclear program, or they can seek a diplomatic solution to their deepening economic and political problems.

Either way, President Trump has indicated he is willing and able to respond.