PRESIDENT Barack Obama's complex, costly and far-reaching strategy for Afghanistan, one that links success there with stability in neighboring Pakistan, embarks on a high-stakes shakedown cruise this week. The leaders of both nations, Pakistan's Asif Ali Zardari and Afghanistan's Hamid Karzai, are in Washington for meetings with Obama, who will emphasize US intentions to build a strong and lasting regional alliance. It's a mission that will take many years, cost billions of dollars, put more American troops at risk and be undertaken against poor odds historically. Obama's aim, administration officials say, is to fully engage both leaders in his grand regional strategy. The idea is to turn both countries into full-fledged US allies, rather than treating them as platforms on which the United States fights militant enemies and then goes home. US failure in either or both countries could add vastly to threats to US security. Fighting rages in both nations, primarily against Taleban militants – the fundamentalist Islamic force that provides sanctuary for Osama Bin Laden and other Al-Qaeda leaders in the nearly impenetrable mountains that straddle the common border. While diminished since it conducted the Sept. 11 attacks, Al-Qaeda remains robust in its safe haven along Afghanistan's rugged border. A collapse of the democratically elected, secular government in Pakistan, meanwhile, could put the country's sizable nuclear arsenal at risk of falling into militant hands. The Taleban fighters, driven from power by US and allied Afghan forces in the first months after the Sept. 11, 2001 terrorist attacks on the United States, have retaken large swaths of Afghanistan and are now making deep and threatening advances into Pakistan – within striking distance of the capital. Obama will meet together and separately with Karzai and Zardari before he sends them off for detailed briefings at the FBI, the CIA and other intelligence agencies and the State Department. They will sit down with Vice President Joe Biden as well. Last week, Obama said the possibility of Pakistani nuclear weapons falling into militant hands was not an immediate worry, but that he remained deeply concerned about the dangers advancing on the region. “I'm confident that we can make sure that Pakistan's nuclear arsenal is secure,” Obama said at his last news conference. Asked Monday about whether the sensitive issue of nuclear security would come up at the talks, White House spokesman Robert Gibbs said, “I don't doubt that that will be mentioned.” But Gibbs said the president would be spending “a lot of time” trying to reinforce his new strategy, one that ensures the United States will “finally have a regional approach.” In the longer term, Obama has said he is “more concerned that the civilian government there right now is very fragile” and doesn't “seem to have the capacity to deliver basic services ... for the majority of the people.” To help, Obama has asked Congress for quick approval of hundreds of millions of dollars in emergency military aid for Pakistan and is backing an aid package providing $7.5 billion over the next five years. In Afghanistan, Obama is deploying 17,000 more US troops into the south and east of the country, while working at the same time to ease humanitarian suffering in the desperately poor country. The plan for both nations is to militarily defeat the resurgent Taleban while boosting domestic support for the governments through aid programs. The ravages of Afghanistan's 10-year occupation by the Soviet Union in the 1980s, a long period of brutal Taleban rule through the 1990s and now nearly eight years of US-led fighting since 2001 also deeply undermined Pakistan. That means US strategy now relies in propping up both countries. While administration attention now focuses heavily on Pakistan, Afghanistan's Karzai may be approaching his own visit with some sense of vindication. Since his election, Obama has been rough on Karzai, calling him ineffective and his government corrupt. But in the last couple of weeks, Karzai scored a major political coup by persuading the main challenger for this year's presidential election, provincial governor Gul Agha Sherzai, not to run. Karzai's nearly certain re-election means the Obama administration will have to deal with the Afghan leader for the remainder of the US president's term. On March 27, Obama presented his realigned plans for dealing with the Afghan war, a strategy that includes Pakistan as a potential partner rather than a nation reluctant to help fight the Taleban. Wednesday's meetings will offer a glimmer of how that's working so far.