Condoleezza Rice said a negotiated deal with the Palestinians was preferable, but seemed unlikely since the militant group Hamas won Palestinian elections.
But she added that there had been no chance to discuss the Israeli proposal.
It is the first time the US appears to have dropped its insistence that the conflict must be solved bilaterally.
Ms Rice was speaking to reporters travelling with her to Berlin for talks about Iran’s nuclear programme.
‘No chance to talk’
Ms Rice pointedly did not rule out supporting Kadima’s plan for withdrawing from parts of the occupied West Bank by 2010 but consolidating other Jewish settlements there.
“I would not on the face of it say… that we do not think there is any value in what the Israelis are talking about,” she said.
“But we can’t support it because we don’t know. We haven’t had a chance to talk to them about what they have in mind,” she stressed.
She referred to Hamas’ victory on a platform of resistance to the Israeli occupation and opposing negotiated settlements.
“If you are going to have a negotiation you have to have partners and the Palestinian government does not accept the concept of a negotiated solution,” Ms Rice said.
After winning Tuesday’s general election, Kadima will become the largest party in the next Knesset, although it will need at least two coalition partners to get a parliamentary majority.
Efforts to form a coalition will begin officially on Sunday, when the largely-ceremonial president, Moshe Katsav, will chair the first formal negotiations.
But Kadima’s leader, Acting Prime Minister Ehud Olmert, has already insisted he will keep the powerful finance ministry in any new government, the Maariv newspaper has reported.
Such a stance could complicate negotiations with Kadima’s most likely partner, the Labour party, which wants the finance portfolio to help it to reverse the extensive welfare cuts of recent years.
A senior Labour MP, Yuli Tamir, said not getting control of the ministry would be a red line for her party joining the government.
“There is no doubt that our demand for the Finance Ministry is a legitimate one and part of our world view,” she told Israel Army Radio.
Kadima is expected to ask a number of other smaller parties to join its coalition, including the Pensioners’ Party and the ultra-orthodox Shas and United Torah Judaism parties.
Mr Olmert was also called by the Palestinian leader, Mahmoud Abbas, who offered congratulations on his election victory.
The two men did not discuss the possibility of holding talks in the near future, a spokesman for the prime minister said.
Source: BBC News