WASHINGTON — Ever since Britain declared 100 years ago that there should be a Jewish homeland in Palestine, harmony has eluded that dry, benighted land. Presidents and kings and prime ministers and diplomats and special envoys have labored for a century in a futile search for peace.

President Trump, however, is not daunted by the challenge of bringing together Israelis and Palestinians. “It’s something that, I think, is frankly maybe not as difficult as people have thought over the years,” he said on Wednesday.

Whatever else may be said of him, Mr. Trump does not suffer from a confidence deficit. As he hosted the Palestinian leader, Mahmoud Abbas, Mr. Trump proclaimed that he would be the president who finally makes peace in the Middle East. “We will get this done,” he said. He even suggested that, with his leadership, “hopefully there won’t be such hatred for very long.”

Never mind that he also thought repealing and replacing his predecessor’s health care program would be “so easy.” Or that he predicted he would have no trouble bending North Korea to his will, or forcing Mexico to pay for a border wall. Then there was Mr. Trump’s assertion as a candidate that he knew more about the Islamic State than the generals. And his insistence that he could “fairly quickly” pay off the entire $19 trillion national debt accumulated over the last 182 years.