When you are dealing with a conflict that has gone on for a very long time, it is wise not to infer too much from a single meeting between two men who are new to their jobs.

But new leaders usually have a better chance of changing things than they do after they have been bruised and battered by a few years in office, so it does not do to be too cynical either.

Before the meeting between US President Barack Obama and Israel's new prime minister, Benjamin Netanyahu there were predictions of a rift between them.

There are precedents. When Mr Netanyahu was prime minister between 1996 and 1999, he had a difficult relationship with President Bill Clinton.

But if that is going to happen with President Obama, it is probably too early, and the rest of us are not likely to hear about it for a while.

Two leaders anyway do not have to be best buddies to run an alliance.

Do not forget that there are important links between the United States and Israel that are about as immutable as anything else in international affairs.

Ever since President Harry Truman gave Palestine's Jews vital diplomatic help when they were creating the state of Israel in 1947-48, the relationship has become closer and closer.

At the moment Messrs Obama and Netanyahu are agreed that they do not want Iran to get nuclear weapons.

That has been apparent for some time. Iran denies they are developing a weapon, but its arguments are not winning many of the sceptics over.

The Israeli government does not have much faith in the Obama administration's plan to talk Iran out of enriching uranium.

But it can hardly tell the president not to try.

Mr Netanyahu would have liked a tough deadline to be built into any talks, when they start properly.

Instead President Obama promised to view the way they are going at the end of the year. It is a deadline of sorts.

But does it just give the Iranians a warning that by December they need to have found a way to play for more time?

On the Palestinian front, President Obama reiterated his belief that the best chance of peace lies with the creation of a Palestinian state alongside Israel.

He emphasised Israeli as well as Palestinian obligations.

For example, he said that Israel was right not to tolerate its citizens being rocketed from Gaza.

Then he went on to say that Israel needed to loosen its blockade of the territory because despair in Gaza was bad for peace and bad for Israeli security.

Mr Netanyahu, on the other hand, does not believe in Palestinian independence.

He talks about a plan for economic peace and limited self-government, which he says is necessary because otherwise Israel would open itself up to unnecessary risks.

He warns that Palestinian independence in east Jerusalem and the West Bank could create a forward missile base for Hamas and Iran.

Collision course?

The starkly different views of a Palestinian state mean President Obama and Prime Minister Netanyahu have built the chance of a collision into their new relationship.

President Obama is expected to announce a new peace plan in a speech in Cairo on 4 June.

If it is to be serious, it will have more details that Mr Netanyahu and his mainly right-wing coalition will find hard to swallow, especially on the continuing expansion of Jewish settlements in the occupied Palestinian territories, which is against international law.

Officials who are travelling with Mr Netanyahu are talking confidently to Israeli journalists who are travelling with them, suggesting that any problems will be ironed out in joint US-Israeli work committees that are being set up.

It might not be that easy.

Israel and the US are natural allies. But only partially obscured by the mutual compliments at the White House were differences of tone and substance that would have been inconceivable under President George W Bush.

If President Obama is serious about making peace in the Middle East, tough choices will be required from all sides, and that means there could be some bumpy moments ahead in the relationship between Israel and its best friend.