Twenty years ago this week, the first Oslo Accord was signed in Washington. Shaking hands on the White House lawn before US President Bill Clinton, Israeli Prime Minister Yitzhak Rabin and Yasser Arafat, chairman of the Palestine Liberation Organization (PLO), agreed to embark on a peace process to end decades of conflict.

I remember that day well. Along with a great many people across the world, both within and outside the Middle East, I was hopeful about the historic agreement. As prime minister of Norway at the time, I also felt a sense of joy that the talks between the Israeli and Palestinian negotiators who had worked tirelessly in secret over the previous nine months, in and around Oslo, had produced unexpected results.

The Israelis and the Palestinians had made a breakthrough of tremendous significance, recognizing each other’s legitimacy for the first time. The agreement was to be the first step on the road to a permanent resolution to the conflict, based on the principle of two states — one Israeli, one Palestinian — living side by side in peace.

But the story since that day has been one of bitter disappointment, punctuated by surges of confrontation. Cycles of violence and recrimination have derailed the Oslo process. The tragic assassination of Prime Minister Rabin in 1995, the violence committed by both sides during the second intifada of 2000-2005, the blockade of Gaza and the split in the Palestinian camp were only a few of the countless blows to the peace process.