The latest round of violence between Israelis and Palestinians is happening because the long and unresolved conflict between the two sides has once again been left to fester. It is an open wound in the heart of the Middle East and it is why violent face-to-face confrontations have escalated into rocket-firing, air strikes and death.
Just because the conflict has fallen out of international headlines in recent years does not mean that it has ended. The issues do not change, neither does the hatred and bitterness that not years but generations of trouble and killing have engendered.
For more than a century, Jews and Arabs have struggled to be the masters of the land between the River Jordan and the Mediterranean Sea. Israel has inflicted a series of crushing defeats on the Palestinians since it became independent in 1948, but it still cannot win.
While the conflict goes on neither side can be secure. The one certainty is that every few years, at least, there will be a serious and violent crisis. The pattern over the past 15 years or so has often involved confrontation across the wire separating Gaza from Israel.
This time there has been a reminder that events in Jerusalem and its holy sites have an unmatched capacity to ignite violence.
The city’s sanctity for Christians, Jews and Muslims is not just a religious matter. The Jewish and Muslim holy places are national symbols too. Geographically they are, literally, a stone’s throw apart. The Holy Sepulchre church is close by, on the other side of an Israeli checkpoint, venerated by Palestinian Christians.
The triggers included threats to evict Palestinians from their homes in Sheikh Jarrah. It is a Palestinian neighbourhood outside the walls of the Old City, with land and property claimed by Jewish settler groups in the Israeli courts.
That was more than a dispute over a handful of homes. It comes after years of successive Israeli governments pursuing the strategic objective of making Jerusalem more Jewish. Big settlements for Jews were built on occupied land to ring the city, breaking international law. In recent years the government and settler groups have worked to settle Jewish Israelis in Palestinian areas near the walled Old City on a house-by-house basis.
Added to that in the past few weeks was heavy-handed Israeli policing of Palestinians during Ramadan, culminating with the use of CS gas and stun grenades inside al-Aqsa mosque, the holiest place for Muslims after Mecca and Medina.
Hamas took the unusual step for them of issuing an ultimatum to Israel to remove its forces from the al-Aqsa compound and from Sheikh Jarrah, and then fired rockets at Jerusalem.
Israeli Prime Minister Benjamin Netanyahu tweeted that “the terrorist organisations in Gaza crossed a red line… Israel will respond with great force”.
Another combination of events could have ended up the same way. Violent events will happen again and again while the conflict is left unresolved.
I was asked by a BBC presenter on Monday, as the crisis was escalating, when was the last time I found any sense of hope in Jerusalem that the two sides would find a way to co-exist in peace. I lived in Jerusalem from 1995 to 2000 and have been back since many, many times.
Finding an answer was difficult. At the high point of the Oslo peace process in the 1990s there was a brief moment of hope but only residents of Jerusalem who are the wrong side of 40 years old or so will have much of a memory of how it felt.
Leaders on both sides have been fighting their own domestic political battles, concentrating on safeguarding their own positions, when the biggest issue for any Palestinian or Israeli leader should be making peace. That challenge has not been addressed seriously for years.
Some new ideas have emerged. Two respected think tanks, the Carnegie Endowment for International Peace and the US/Middle East Project have just released a joint report arguing that the first priority should be equal rights and equal security for both Palestinians and Israelis.
It says the United States should support “full equality and enfranchisement for all those residing in the territory under Israeli control; it will not endorse two separate and unequal systems”.
New thinking is good. This week though old realities, familiar rhetoric and the latest inevitable eruption of a century-long conflict are drowning everything else out.