(CNN) -- In a joint opinion piece to be published Friday, the leaders of the United States, Britain and France lay out in stark terms their contention that Libya's future must not include its leader, Moammar Gadhafi.
"It is unthinkable that someone who has tried to massacre his own people can play a part in their future government," said the article, titled "Libya's Pathway to Peace," by U.S. President Barack Obama, British Prime Minister David Cameron and French President Nicolas Sarkozy. "It would be an unconscionable betrayal."
The article, which is slated to appear in the International Herald Tribune, Le Figaro, and Times of London, was sent to reporters by the White House.
Because Gadhafi has lost the consent of his people, "any deal that leaves him in power would lead to further chaos and lawlessness," it says. "We know from bitter experience what that would mean. Neither Europe, the region, or the world can afford a new safe haven for extremists."
The leaders called for an end to violence and for the regime's forces to pull back from the embattled cities of Ajdabiya, Misurata and Zintan, which have been besieged by Libyan government forces.
"However, so long as Gadhafi is in power, NATO must maintain its operations so that civilians remain protected and the pressure on the regime builds," they wrote. "Then a genuine transition from dictatorship to an inclusive constitutional process can really begin, led by a new generation of leaders. In order for that transition to succeed, Gadhafi must go and go for good."
At that point, they added, "the United Nations and its members should help the Libyan people as they rebuild where Gadhafi has destroyed -- to repair homes and hospitals, to restore basic utilities, and to assist Libyans as they develop the institutions to underpin a prosperous and open society."
The decision about who will replace the current Libyan leaders will be left up to the Libyans themselves, they said.