In Iraq, the administration has bet everything on a future that will not happen: Iraqis rallying behind a strong central government. It has ignored the need for a political solution based on federalism that gives local control to Iraq's warring factions. By stubbornly sticking with a failed policy, it is frittering away the diplomatic capital and resources it needs to deal with other challenges.

In Lebanon, two years after the Cedar Revolution, the administration has delivered little military assistance to the embattled government, while Iran and Syria lavish Hezbollah with arms and cash.

In the Palestinian Territories, the administration overruled Prime Minister Sharon and many Palestinians and insisted that the January 2006 legislative elections go forward, despite having failed to empower Palestinian President Mahmoud Abbas. The result was a Hamas victory.

Now, the administration is taking regional diplomacy more seriously. But its efforts to undo the damage of the past six years are leading it to new strategic miscalculations.

The administration subcontracted to Saudi Arabia the power to broker a deal for a national unity government between Abbas' Fatah party and Hamas, without insisting on red lines any deal could not cross.

Hamas now has what it most craves -- legitimacy in the eyes of the Arab world, which could serve as a bridge to wider international legitimacy. It gives up nothing in return. The Mecca agreement does not require Hamas to meet the demands of the Quartet (the United States, the European Union, Russia and the United Nations): recognize Israel, renounce violence and accept past agreements. Mecca has undercut the administration's most ambitious involvement in the peace process and its belated effort to bolster Abbas.

Even without Mecca, the administration's renewed interest in Israeli-Palestinian peace is driven by flawed logic: the desire to gain greater cooperation from moderate Arab countries -- Egypt, Jordan, Saudi Arabia and the other Gulf States -- in containing Iran's expanding influence.

Those countries have a powerful self-interest in diminishing Iran's influence that requires no inducements. They should be taking risks to support Israeli-Palestinian peace so as to ease regional tensions and isolate Iran. If the Saudis and others mean what they say about wanting a two-state solution, now is the time to begin the process of normalizing relations with Israel.

Meanwhile, authoritative reports say that the administration is telling Israel not to talk to Syria. Syria's overtures may not be sincere, but Israel should be permitted to call its bluff.

A Syrian-Israeli peace process could have significant strategic benefits. It could place pressure on the Hamas leadership in Damascus and strain the Iranian-Syrian marriage of convenience. Combined with U.S.-Syrian engagement, it could reduce Syria's destructive influence in Lebanon and limit Hezbollah's room for maneuver. Syria's behavior in each of these areas has worsened during the period the administration has shunned direct engagement.

The Middle East has entered a tumultuous period that demands more -- not less -- diplomacy. The priorities should be:

• Restore American credibility and flexibility through an all-out effort to achieve a political settlement in Iraq and redeploy our combat troops by 2008. To learn the details of my proposal, visit www.planforiraq.com.

• Urgently deliver military aid to Lebanon and shift the balance of power away from Hezbollah; gain U.N. Security Council approval to establish an International Tribunal for the murders of former Prime Minister Rafiq Hariri and others, making moot Syria's efforts to undermine a mixed Lebanese-international tribunal.

• Facilitate, don't prevent, Israeli-Syrian talks. Directly engage with Syria to support such talks and confront Syria's destabilizing actions in Lebanon and Iraq.

• Intensify pressure on Iran over its nuclear program with coordinated international sanctions that isolate Tehran, not the United States; engage Iran directly to exploit fissures within the government and between the government and the people; present a positive vision for U.S.-Iran relations if Iran does the right thing.

• Back Israel's interest in engaging Abbas; demand that the Palestinian National Unity government meet the Quartet criteria; press Arab states to start normalizing ties with Israel; support moderate alternatives to Hamas in the Palestinian territories.

The administration's record does little to inspire confidence that it can tackle this agenda. But the cost of not even trying will be tremendous. Hamas will consolidate its position; Iran's influence will continue to grow; Iraq will descend into chaos and its neighbors will intervene; Syria and Hezbollah will continue to destabilize Lebanon; and the prospects for peace between Israelis and Palestinians will recede even further. That legacy will take a long time to undo.

Sen. Joe Biden, D-Del., is chairman of the Senate Foreign Relations Committee.

© 2007 Miami Herald Media Company.