Warning that it will be the last time he does so, President Trump on Friday waived sanctions on Iran for 120 days.

In doing so, he affirmed that he has the right policy approach to Iran.

That approach is based on deterring and constraining Iran's malevolent activities around the world, strengthening the nuclear agreement's inspections protocols, and cracking down on Iranian ballistic missile development activities.

In turn, the White House says that it will introduce sanctions on 14 individuals and entities, including the head of Iran's judiciary.

But while some were hoping that the Trump administration would pull out of the nuclear agreement today, the Trump administration seems to recognize that the best way to serve U.S. security interests is to persuade the European Union to support improvements to the nuclear deal.

By warning that he will no longer support the nuclear deal as it stands, Trump ensures two outcomes. First, that the Iranian hardliners recognize that the good old days of Obama administration appeasement are over. Second, that European governments must either come to the table to improve the deal or, should the U.S. exit from the agreement, face U.S. sanctions on their corporations that choose to continue doing business in Iran.

Those prospective sanctions will carry a heavy political influence in Berlin, Paris, and London because the U.S. market is far more lucrative to European multinationals than the Iranian market.

And just as important, with the sanctions announced today on various Iranian hardliners, Trump has taken a long overdue step in ensuring moral attention towards Iranian government policies. This moral influencing is perhaps Trump's greatest opportunity: It allows him to play the Europeans at their own game, offering solutions to the Iran deal which impose consequences on Iranian hardliners for abusing their people.

Of course, the coming three months will be full of complaints from both Europe and Iran. Expect Trump's Twitter feed to be active!