U.S. President Donald Trump's opening Middle East move was impressive, and even crushing. His historic visit to the region included a stop in Israel, and his decisive rhetoric was backed up by action -- the airstrike in Syria -- demonstrating that his intentions are serious. He doesn't just talk. He also shoots. But after the enthusiasm came disillusionment. The situation in Syria remains grim, as Syrian President Bashar Assad continues to maintain his power. In the Persian Gulf, the moderate Sunni states established a united front, not against Iran, as Trump implored them to do, but against Qatar. As for the Israeli-Palestinian conflict, it seems that every step forward -- such as the promise to move the U.S. Embassy to Jerusalem -- is followed by two steps back. In this respect, the arrival in Israel of Trump's advisers, son-in-law Jared Kushner and mediator Jason Greenblatt, suggests that the White House does not intend to back down or slow down, but rather remains determined to advance peace between Israel and the Palestinians. In Israel, many are skeptical of the possibility of a significant diplomatic initiative. Because, despite what Washington may believe, the Israeli-Palestinian conflict is not a conflict over real estate. Simple compromise on price or plot size will not resolve it. It seems the ones who are the most disturbed by the American attempts to restart negotiations are actually the Palestinians. They have grown accustomed, over years of successive American administrations, to the U.S. demanding concessions of Israel not in exchange for peace but just to obtain Palestinian willingness to negotiate. The Palestinians have collected Israeli concessions one by one throughout the years. They have ended up with a great deal of property, which served as something of a deposit or a comfortable starting point for the next round of talks. This time, the American approach is quite different. It does not make preliminary demands of Israel, but rather of the Palestinians, who must now prove the sincerity of their stated intention to combat terrorism. After all, for Trump, terror is terror, and the salaries and support provided by the Palestinian Authority to the families of attackers are unacceptable. This poses quite a challenge for the Palestinian leadership as it enters talks with Israel: It must forgo Israeli concessions while simultaneously facing Palestinian public opinion that supports terrorist attacks against Israelis. How will they surmount this challenge? Only Palestinian Authority President Mahmoud Abbas and U.S. President Donald Trump know the answer.