Mrs Clinton has backed a two-state solution - but is time running out?
By Jeremy Bowen
Middle East editor, BBC News
A journey to Ramallah from Jerusalem tells you a lot about the state of peace and war between Israel and the Palestinians.
US Secretary of State Hillary Clinton does not get the delays at checkpoints that most people face.
But if she looked out of the window of her armour-plated SUV she would have seen some of the ways this place is changing, and why that undercuts the policy that she is here to promote.
Throughout her visit, speaking to Israelis and Palestinians, Mrs Clinton has been saying that she wants to create a Palestinian state alongside Israel - the so-called two-state solution to the conflict.
The security walls appear to symbolise the lack of trust on both sides
She says that making a Palestinian state possible is a commitment she carries in her heart, not just in her portfolio as secretary of state.
But when others who also believed for years in two states look out of their car windows at what is happening in the West Bank and Jerusalem, they cannot help thinking that their dream has gone.
Big chunks of the land that Palestinians want to use for their state has been taken for Jewish settlements, for the network of security roads and military bases that protect them and connect them to Israel, and for the complex of walls and hi-tech fences that make up the separation barrier.
And as the land goes, so does trust, on both sides.
Palestinians find it easy now to ignore politicians when they talk about peace, because they have heard it so many times before.
The years of violence have also worn down Israelis. Many who used to think a Palestinian state would make their lives safer and more secure now think it would turn into Greater Hamastan - a bigger version of Gaza and an easier place to use as a base for launching rockets into the heart of Israel.
More than vigour
Even those who still have some hope that the two-state solution is possible and desirable believe that the next few years are the last possible opportunity to make it happen.
Mrs Clinton's words have been almost indistinguishable from those of her predecessor Condoleezza Rice
Mrs Clinton hinted at that herself. She said that time was of the essence, and that the Obama administration was going to work vigorously to get the two sides to make an agreement.
It will take more than vigour. The Israeli Prime Minister designate, Benjamin Netanyahu gets his core support from parties who reject the idea of a Palestinian state.
If they dominate his governing coalition - when and if it is formed - then a collision with Washington looks inevitable, if President Obama and Secretary Clinton are as keen as they say on two states.
For this to work, the Americans are going to have to persuade the Israelis that their security will be enhanced, not jeopardised. In the current climate that will be difficult.
The Americans will also have to show Palestinians that they are prepared to lean on their Israeli friends. Pressure on Palestinians costs nothing for American politicians. In fact its absence can lose them votes.
The decisions taken by Mr Bush made the divisions broader and deeper
But pressure on Israel is an entirely different matter, and it will be necessary if Israel is to stop expanding Jewish settlements in the occupied territories and is to contemplate ever removing some of them.
In her public statements while she has been here Mrs Clinton's words have been almost indistinguishable from those of her predecessor Condoleezza Rice. Both women called for peace and for a state called Palestine alongside Israel, and both said they would work to make it a reality.
By the time Secretary Rice left office the vision looked as distant as ever. The difference between them hinges on the determination of their bosses.
Former President George W Bush always seemed to be paying lip-service to the project.
What Palestinians and Israelis do not know yet is whether President Obama will be different. His intentions seem clear, but he has a very crowded and complicated agenda.
In the Middle East alone, what he does with the Israelis and the Palestinians will be shaped by what he also wants to do across the Arab and Muslim countries of the world.
And the fault lines in the small area that makes up Israel, the West Bank and Gaza have a habit of producing challenges that demand action.
The decisions taken by Mr Bush made the divisions broader and deeper.
It will be clear soon enough whether President Obama has what it takes to bridge the gaps, and even close a few of them.