A self-described optimist, former British Prime Minister Tony Blair told Congress on Thursday there is no workable alternative to a two-state solution to the long and bloody conflict between Israel and the Palestinians, and both sides are in favor of it.

But in practice, "they doubt it can happen," Blair told the Senate Foreign Relations Committee.

"The opportunity is there," said Blair, who is the international negotiator for the Mideast on behalf of the United Nations, the United States, the European Union and Russia. "But it won't remain if not seized. As President Obama has recognized, this is the right time to seize it."

The best way to go, he said, is to try to make it clear to the Palestinians that negotiations will result in genuine statehood and to the Israelis that there can be "an agreed program for reform of the Palestinian security sector."

On the Israeli side, he said, Israel will not agree to a Palestinian state unless it knows its neighbor will be secure, stable and well governed.

Next week, President Barack Obama will immerse himself in trying to point Israeli Prime Minister Benjamin Netanyahu toward negotiations with Mahmoud Abbas, the Palestinian president.

Netanyahu is reluctant, on the grounds Israel cannot be sure of an end to violence. Abbas is reluctant to negotiate for an agreement with the Israeli leader until he agrees to freeze construction of Jewish homes on territory occupied by Palestinians.

But, differences aside, Blair said the time for peacemaking is opportune, with the Arab countries agreeing to recognize Israel, provided it agrees to a Palestinian state that includes all the land captured by Israel in the 1967 Mideast war.

Blair urged Obama to push quickly for negotiations, provided it clearly points to genuine Palestinian statehood.

Members of the Senate panel appeared to agree there was no alternative to negotiations.

"We all understand," said the committee chairman, Sen. John Kerry, D-Mass., "that peace will not come to the Middle East quickly or easily."

But, Kerry said, "I share Mr. Blair's optimism that this moment presents an opportunity we cannot afford to miss."