The choice of Joe Biden as candidate for veep made me recall a conversation with him at the 2004 Democratic convention.

The Delaware senator was fuming that his party’s nominee, Sen. John Kerry, wouldn’t go on the offensive. Biden wanted Kerry to attack Bush failings on national security.

“He has to talk specifics,” Biden argued passionately. “When you talk in generalities, people say, ‘Blah.”‘ The candidate shouldn’t just cast blame, the senator added, but should spell out his own plans.

In 2008, Democrats are eager to attack Bush foreign policy. But their presidential candidate is light on experience, and his oratory tends toward the philosophical. Enter Joe Biden, one of the most seasoned foreign-policy actors in the Senate.

Can the earthy Biden help Obama convince voters that the Democrats are best placed to handle national security and reverse Republican errors?

Having watched Biden’s feisty speech in Springfield, Ill., after being tapped, I think he may be more valuable in making the Democrat’s case on the economy to undecided voters. A son of working-class Scranton, Pa., parents, he addressed the economic pain of the middle class much more directly than Obama. Despite his reputation for verbosity, Biden was punchy and succinct.

Yet Biden can also be a foreign-policy asset to Obama as a sounding board and adviser. After eight years of ideologues in the White House, Biden’s pragmatism may be a useful corrective. He is a liberal internationalist, willing to use force if necessary as a last resort. But he’s long grasped the need to use economic and diplomatic measures to confront Islamist terrorism.

Late in the day, the Bush White House has recognized that these are essential components of a counterterrorism strategy. Condi Rice is doing things now that Biden recommended years ago.

Biden warned early that the White House was wrong to resist efforts at nation-building in Afghanistan after defeating the Taliban. Now, the Taliban is back, and the White House is finally following Biden’s prescription – seven years too late.

Biden was also ahead of the curve on Pakistan, warning of the need to strengthen civilian institutions. Seven years of White House support of military leadership by Pervez Musharraf, and $1 billion in military aid, have created a mess in which jihadis are now taking over huge chunks of a country with nuclear weapons. Biden has proposed a smart package of civilian aid to Pakistan aimed at building roads, schools and clinics, including in tribal areas where jihadis now hold sway.

The Democratic left takes Biden to task because he voted to authorize the use of force in Iraq (the right is targeting his mistaken opposition to the first Gulf War). But Biden tried hard in 2002 to yank the administration’s focus back to diplomacy and destroying Saddam’s weapons via tougher U.N. resolutions.

He held prewar Iraq hearings with Sen. Richard Lugar, R-Ind., that were the first to alert the nation to the complete unpreparedness of the Bush team for handling the postwar. It isn’t his fault he failed.

The senator’s 2006 plan for soft partition of Iraq into Kurdish, Sunni, and Shiite regions was wrongheaded; we could not impose a formal division of the country that its Arab population didn’t want. I would hope his keen interest in Iraq would compel him to take a realistic post-election look, should the Democrats win, at what’s a responsible exit strategy from Iraq.

In the best case, his pragmatism and experience – traveling repeatedly to hot spots – would leaven Obama’s outlook. He could also carry an important message to voters: that a broad security strategy for the Mideast and beyond needs much more than force. And that attacking Iran would create more ugly problems than it solves.

That said, I still think Biden’s best bet is to deliver an aggressive message on how Democrats can do better on the economy. A direct message that rises above the blandness of “blah.”