When Hillary Rodham Clinton announced that the US had invited the leaders of Israel and the Palestinians to resume direct peace talks next week, the secretary of State did not mince words about the obstacles to success.

“The enemies of peace will keep trying to defeat us and to derail these talks,” she said Aug. 20. That is why the negotiations will need “actions by all sides” to support the process.

Palestinian West Bank leader Mahmoud Abbas and Israeli Prime Minister Benjamin Netanyahu need to be ready for possible stepped-up violence from Hamas – the Palestinian militants in charge of Gaza – and for protests or provocations from Israeli settlers in the West Bank who don’t want to cede one inch of territory to a new Palestinian state.

The two leaders must also be prepared for opposition within their own political camps – opposition based on mistrust of the other side, on history, and on fear that too much will be given away.

All of this is why, as Secretary Clinton emphasized, the two leaders will need active support. It helps that Jordan’s King Abdullah and Egypt’s president, Hosni Mubarak, will join the negotiators Sept. 1 for meetings and a dinner with President Obama. They’ve already made peace with Israel and their presence will send a signal of hope in the face of a widespread skepticism about the talks.

But more than signals and symbolism are required.

Saudi Arabia and other Arab states can concretely show that normal relations with Israel lie at the end of a two-state peace agreement. They can prove their good faith by following through on confidence-building gestures requested by Mr. Obama last year, including allowing Israeli commercial aircraft overflight rights.

The international community can show its willingness to help solve thorny issues such as a Palestinian “right of return.” It’s understood they won’t come back to Israel, except in a few cases, but they’ll demand compensation for lost property costing billions. The world can commit to helping with the cost.

The US must have its own proposals for peace ready to offer, much as Bill Clinton did at the failed Camp David talks in 2000. The general outlines of a deal have been known for a long time, including sharing Jerusalem as the capital of both countries. But the devil is in the details and that’s where Washington comes in. The US will have to give shape to the broad parameters and build international consensus in order to bolster the leaders on both sides.

The leaders themselves will also have to support this process. Specifically, Mr. Netanyahu should continue with a moratorium on new settlement construction in the West Bank set to expire Sept. 26. Mr. Abbas and his able prime minister, Salam Fayyad, must carry on with significant Palestinian improvements in West Bank security.

A general atmosphere of gloom and skepticism precedes these talks, with the political barometer pointing to storms ahead.

But with a conservative such as Netanyahu professing to be serious about a two-state solution, these negotiations represent a Nixon-to-China moment for the prime minister. As for Abbas, he and his predecessor, Yasser Arafat, have let previous offers slip by. He and all Palestinians can’t afford to say no any longer.