Each president brings his own unique preconceptions to the job. Post-depression, FDR believed the American people deserved a "New Deal." John Kennedy felt Americans would willingly "pay any price" to spread freedom and democracy throughout the world. Ronald Reagan thought a strong national defense would bring the "evil empire" to its knees. A post-9/11 George W. Bush saw radical Islam as the single greatest threat to western style democracy.

As a candidate and as President, Barack Obama, too, has been quite clear about the fundamentals of his foreign policy—particularly America's approach to the world's dictators and assorted miscreants. He would sit down and talk with them "without preconditions." A new era of diplomatic engagement would emerge. A more acquiescent America would generate a resurgence of good will among Muslim nations. Mr. Obama would convince Israel that "land for peace" could be achievable even if the Palestinians continued to oppose the very existence of the Jewish state. And he would "restart" a bilateral relationship with George W. Bush's nemesis, Vladimir Putin. 

Yet, bad actors have a way of spoiling even the most heartfelt attempts at high rhetoric and good deeds. And today's bad actors are deep into the process of challenging the President's primary assumptions. 

The latest shenanigans in Ukraine offer a stark example. Here, the President's sanctions regime has had little impact as Mr. Putin proceeds to dismantle eastern Ukraine one zip code at a time. A mocking response to U.S. and western military actions only further underlines the point.

Similarly, Mr. Obama's constant lobbying of Bibi Netanyahu's conservative government has generated no good will with Palestinian President Mahmoud Abbas, who refuses to recognize any parcel of Israel as a legitimate Jewish state. Now, Mr. Abbas has agreed to form a unity government with terrorist-affiliated Hamas. Neither has tough talk dissuaded the rogue nuclear ambitions of Iran, where the Holocaust-denying Ayatollah Khamenei and alleged "moderate" President Hasan Rouhani have negotiated a bomb making deal with the West on a slower timeframe—to the utter consternation of Israel, its moderate Arab neighbors, and many Members of the United States Congress.

Further, repeated instances of chemical gas attacks against his own people has proven a consequence-less act for Syrian dictator Bashar Assad. The Administration's feckless threats regarding "lines in the sand" were exposed in the process.

One quality that distinguishes a dynamic leader is the ability to change course (and preconceptions) midstream when it becomes clear that what you are doing is not working. All of which begs a critical question: Can an instinctively anti-war president recognize that his moral entreaties to bad people are simply ineffective and that his vast reservoir of charisma is lost on tin horn dictators and murderous autocrats willing to do anything to preserve their power? The answer will define the President's foreign policy legacy.