By Jonathan Beale
BBC News, the United Nations
Israel is America's ally. When Israeli troops are captured by Hezbollah, the immediate sympathies of the United States lie with Israel.
Is there anything the US can do to put out the flames?
President George W Bush and Israeli Prime Minister Ehud Olmert both say that they're fighting a war on terror.
They have common enemies - radical Islamic extremists willing to use violence.
Both view Hezbollah as a terrorist group. Both see the hand of Syria and Iran in supporting Hezbollah.
But Israel's military action against Lebanon has huge complications.
The US has been supporting Lebanon's independence and leading calls for an end to Syria's interference in the country.
Yes, America is concerned that Hezbollah is still a political force in the country and represented in the government.
It has called on Lebanon take steps to disarm Hezbollah.
But America wants to strengthen - not weaken - Lebanon as an independent state.
When Israel targets Lebanon, it undermines those efforts and increases the sectarian divide in a country that is trying to emerge from decades of civil war.
Then there are the broader regional issues.
The US fears that this is a deliberate attempt by Tehran and Damascus to provoke Israel and divide international opinion.
Is this also an attempt to divert attention from Syria's interference in Lebanon and the controversy over Iran's nuclear programme?
Is it an effort by those countries to further feed Muslim anger against America?
Will there be repercussions for America's presence in Iraq?
The alarm bells have already sounded.
Iran's President Mahmoud Ahmadinejad has warned that any Israeli attack on Syria would provoke a fierce response.
This has the potential to spark a wider conflict in the whole region.
So what can the United States do?
It can hardly condemn Israel for its response to an act of "terrorism".
At best President Bush can urge restraint.
The question is how much pressure does the US place on Israel.
Israel has bombed Lebanese targets after warning leaflets
In public, US Secretary of State Condoleezza Rice has already stepped up that pressure.
Speaking on her way to the G8 summit, she said it was "extremely important" that Israel exercised restraint in its acts of self-defence.
In private those messages will be put more forcefully.
America hopes that restraint by Israel can avoid a split in the international community.
The US does not want to be the only country left defending Israel's actions.
Washington wants to turn international condemnation towards Hezbollah, Syria and Iran instead.
But it is very hard to see how the US can turn the current crises in Lebanon to its advantage.