(CNN) -- The search for Middle East peace requires bold leadership from the United States and an American mediator who is credible, a former adviser to six U.S. secretaries of state, Aaron David Miller, told CNN's Christiane Amanpour Friday.
"The key issue now is whether Israelis and Palestinians can reach an agreement on the four core issues that drive their conflict: border, security, Jerusalem, and refugees," Miller said.
"That needs to be the focus. If not, we've got to find this out because 10 years after Israeli-Palestinian negotiations began, we still don't know."
His comments came as the United States struggles to broker a deal between the Israelis and the Palestinians. U.S. President Barack Obama entered office in January promising a new focus on the conflict. He appointed a Middle East peace envoy, George Mitchell, whose efforts have failed to break the deadlock.
Israeli Prime Minister Benjamin Netanyahu is refusing to order a total freeze on all new Jewish settlement construction on the West Bank and in East Jerusalem as the Obama administration originally demanded. The United States has stepped back from that position, leading to uproar among Palestinians. The president of the Palestinian Authority, Mahmoud Abbas, has threatened to resign, which could lead to the collapse of the Middle East peace process if he does.
An Israeli journalist who works for Ha'aretz as a "correspondent in the occupied lands" for the Israeli newspaper criticized Israeli policy on Amanpour's program. The journalist, Amira Hass, is a frequent and outspoken critic of Israeli actions in the Gaza and the West Bank. She said the idea of a two-state solution to solve the conflict is long dead.
"It is one state now. It's one Israeli government which decides about the future and the well-being of two peoples who live in the same territory between the river and the sea, but they don't have the same rights."
"They are confined to two different sets of laws, of infrastructures, of judicial systems, of education systems, so there's a form of apartheid, a word that nobody likes to hear."
Miller said the issue of Jewish settlements is the biggest problem confronting peace negotiators. "Settlements are a huge problem," he said. They prejudice and predetermine the outcome of negotiations. They humiliate Palestinians."
Hass, who lives in the Palestinian city of Ramallah on the West Bank, told Amanpour that there are two peoples in one territory, but they do not have the same rights. "People in Ramallah do not have the right to travel to Tel Aviv. But every Israeli in Tel Aviv has the right to move to Beit El, a settlement near Ramallah, and be a full Israeli citizen." She described Israel as a "colonialist society."
Miller, though, said the picture was more complex than Hass described it. The conflict is not a morality play, which pits the forces of good on the one hand against the forces of darkness on the other, he said.
"Michael Jackson, who's not a preeminent philosopher, wrote a song called 'Man in the Mirror.' And you know what he said? You want to make a change in your life, the place to start is by looking in the mirror."
"Israelis and Palestinians both have to look in the mirror. They haven't sufficiently."