Tony Blair kick-started his tenure as the Quartet's envoy with a visit to the Middle East this week in the midst of renewed international attention to the Israeli-Palestinian conflict. Blair's formal mission is limited to reviving and sustaining the Palestinian economy - essential for peace. To do so, he should eschew calls for an immediate renewal of discussions on a far-off "political horizon" and begin by sticking to the bricks-and-mortar reality of the Israeli-Palestinian conflict - literally.

Blair should lead an international effort to oversee construction of a dedicated transportation link between the West Bank and the Gaza Strip - a multi-use, multimillion-dollar project that will do more than any other single endeavor to resuscitate the Palestinian economy, unifying their society and polity, and reviving hopes for a two-state solution.

Consisting of an elevated multi-lane highway, cargo and passenger train link, telecommunications connections and water and fuel pipelines, this Palestinian super-highway will become a critical lifeline for millions of Palestinians, and a main artery of the future state of Palestine.

This elevated highway would begin and end well within Palestinian-controlled territory - beginning near Gaza City and ending near Hebron, the capital of the southern West Bank, a distance of only some 40 kilometers. Later on, the highway could be extended northward to Bethlehem, Ramallah and beyond. A West Bank-Gaza bridge meets the critical economic and governance needs of the Palestinians, while also safeguarding Israeli security. Critically, this new highway would not be connected to the Israeli road system whatsoever, constructed entirely above or below ground for its entire length that passes through Israeli sovereign territory. The operation of the link would be under Palestinian control, with Palestinian police patrolling the roadway, monitored electronically, and Israeli forces securing its perimeter.

The basis for any eventual political solution to the conflict will be economic, most critically the viability and growth of a Palestinian state. However, since 2001, the Palestinian economy has experienced a sharp decline, with high unemployment, little industry, and hundreds of thousands of people dependent on food aid and humanitarian assistance in order to survive. Gaza especially has suffered due to its isolation the past six years, part of the reason for Hamas' surge in popularity.

By reversing Gaza's isolation, the bridge has the potential to reduce extremism, prevent fundamentalist ideologies from flourishing, and greatly enhance the ability of the Palestinian government to exert its authority over all its territory far more effectively.

Joint construction of a bridge of this magnitude would be a boon for Palestinian and Israeli industries, and foster goodwill among Israelis, Palestinians and the international community - a tangible commitment to a viable Palestinian state beside Israel, sending a powerful signal to the parties.

A fundamental premise of the entire peace process since the mid-1990s was a two-state solution - with a Palestinian state in the West Bank and Gaza Strip described in the Oslo Accords as a "single territorial unit."

In the heady days of Oslo, several abortive attempts were made to create a "safe-passage route" between the West Bank and Gaza. Most usually entailed Palestinians needing to obtain special permits from Israel to make the trip, often traveling in convoys or on buses at specific times of the day. Every instance was predicated on the Palestinian use of the Israeli road network, and thus hostage to ever-present Israeli security concerns. Predictably, when the security environment worsened, the route was shut down, strangling the Palestinian economy. Resuming safe passage on a similar basis is nowadays seen as a patent impossibility, and will remain so well into the future.

Constructing an elevated West Bank-Gaza transport link would require a long-term approach to be successful, with international leadership, in order to achieve the requisite political support from both Israel and the Palestinian Authority, and secure financing for the construction project.

The attempt at a Palestinian unity government has failed in the most disastrous fashion - exacerbating the internal divide between Fatah and Hamas, and between the West Bank and Gaza.

There has been much talk in Washington, Jerusalem and across Middle Eastern capitals about the need to further isolate Hamas and Gaza, and concomitantly strengthen President Mahmoud Abbas' tenuous rule in the West Bank - in effect a "West Bank First" policy. But the West is too adept at hugging moderate Arab allies to death, and in so doing boosting the prospects of their opponents, to think that this strategy will bear fruit.

Rather than cutting Gaza loose, the answer lies in pulling it back toward the West Bank - increasing ties between the two Palestinian territories. Gaza can be pushed off the radar screen - only at everyone's peril: The West, Egypt, Israel and the Palestinians will all suffer if Gaza is allowed to devolve into an isolated, Islamist outpost.

As the international community now searches for a new road map, Tony Blair is searching for an agenda and project to champion. This is that project - an ambitious, substantive assignment, well within his mandate, and continuing the pragmatic, needs-based approach of his predecessor James Wolfensohn but with tremendous symbolism as well. A project that may well generate Israeli-Palestinian goodwill and precipitate more constructive political negotiations.

Ultimately, a West Bank-Gaza link could become a bridge to that "political horizon" diplomats and politicians are so fond of.

Sustainable peace is built on a firm foundation. In this case, concrete.

Jonathan Kolieb is a research associate at The Century Foundation in Washington, D.C.