Illinois Sen. Barack Obama’s selection of Sen. Joseph Biden (Del.) as his running mate understandably is being analyzed in excruciating detail for its political impacts: Will it unite the Democratic Party? Will he help the ticket in the election? Will his prior disagreements with Obama, for example, on the war in Iraq, help or hurt Obama’s campaign?

These are all important questions. But the larger question for voters really is: What would he bring to the job if their ticket is elected? As we’ve learned, particularly during the past eight years with Dick Cheney, a vice president who is smart, aggressive, experienced — and is respected by the president — can have a major impact on our lives.

Biden is clearly all of those things. So if the Democratic ticket wins, how would he approach the job?

I got a chance to see his approach up close one day in early September 1999, when I was U.S. ambassador to Romania. In the aftermath of NATO’s success in stopping ethnic cleaning in Kosovo, Cabinet members and Members of Congress stopped in Bucharest to thank the Romanians for their support of NATO and get a feel for where the Balkan region was going in its aftermath.

Unlike some of the other visitors whose approach was helpful but remarkably relaxed, Biden was a whirlwind of inquiry, analysis and commentary from the time he landed at Otopeni airport.

On the 20-minute drive into the city, he quizzed me on Romanian attitudes, the status of various government leaders and the inside story on Romania’s foreign policy toward Slobodan Milosevic, who was still in power next door in Yugoslavia. Because Biden has known all the major Romanian leaders since the dictator Nicolae Ceausescu, the questions were Ph.D. level, not Romania 101. That was remarkable in itself since he is no specialist on Romania; he could do the same, landing in dozens of nations around the world.

In his meetings with President Emil Constantinescu and others, he thanked them sincerely for their support for NATO — and then he drilled right in on Milosevic: How strong did they think he was in Yugoslavia after the war? How did they evaluate the various leaders of the democratic opposition there — whom he asked about name by name, since he knew each of them personally, too. Unlike the Bush administration, which has been accused of tailoring its version of the facts to match its policy, Biden was trying to learn the facts firsthand to figure out what would be the right U.S. policy.

He also exuded a passion for helping the Serbs leave the failed path of ethnic war for a democratic future. Between meetings, I got a running commentary on his discussions with Bill Clinton as the president had struggled with the tough questions of when and how much military force to use in that war. In the end, air power and diplomacy won the day for NATO. There was no ground invasion and not a single U.S. soldier died in combat.

But Biden was already concerned that the world’s first observation of the extraordinary precision of America’s new high-tech weaponry, particularly launched from the air, would create destabilizing fear in countries like China. Just months after the Kosovo war had ended, he was looking around the next corner — while not losing focus on the immediate issues.

In most of our meetings, Romanian leaders reiterated their strong interest in joining the NATO alliance. At lunch at my house with opposition party leaders, one of them said that NATO membership was important to their country for a reason I’d never heard before.

“If we’re in NATO, we won’t have to worry about NATO attacking Romania over our relations with our Hungarian minority the way you attacked Yugoslavia,” he said. “Since Turkey has been in NATO for decades, you let them do what they want with the Kurdish minority.”

Biden, visibly angry, rose from his chair, leaned across the table, and said: “If that’s why you want to get into NATO, I’ll make sure you never do!”

Cooler Romanian heads assured Biden — and me — that the gentleman was being misunderstood and they were committed to good relations with their Hungarian minority. And in fact they were right. When the opposition came to power a year later, the Hungarian party in Romania supported government. And in 2004, Romania did join NATO — with Biden’s support.

What struck me, beyond the stupidity of that one Romanian comment, was the frank, sincere, passionate statement Biden made of U.S. policy. He knew when to say the right thing in the right way. And the Romanians clearly respected him for it.

The most extraordinary meeting we had was with Petre Roman, president of the Romanian Senate. He had been prime minister in the early 1990s, so of course Biden had met him before. Biden thanked him for Romania’s help in Kosovo and then grilled him on Serbian politics, a subject on which Petre Roman was an expert. In fact, the Serbian democratic leader whom Roman urged the U.S. to work with became the driving force behind defeating Milosevic in the 2000 elections and bringing pro-Western democrats to power in Serbia, where they are today. Biden asked the right guy the right questions.

But as we came out of the meeting, Biden said to me, “What’s that guy so upset about? He looks the way I felt when I chaired my last Judiciary Committee meeting.” He was referring to 1994, when the Republicans won control of the U.S. Senate, relieving Biden of his chairmanship of the Senate Judiciary Committee.

“He’s got some big problem on his mind. Do you know what it is?” he asked me.

I was amazed. Without knowing the latest inside Romanian domestic politics, Biden had read Roman’s body language and knew he was talking to a politician under incredible stress.

In fact, Petre Roman was under great pressure because the public support for the coalition government, which included his party, was plummeting. Roman was worried about his party’s survival in the next election in 2000. Several months later, he brought down the government, replaced the prime minister and took over the foreign minister’s job himself.

Roman’s party survived the next election, though it went into opposition. But Roman himself was deposed as party leader less than two years after the meeting with Biden.

My question was: How does Biden do it?

I still want to know.

Joe Biden has better intuition about other politicians, American or foreign, than any elected official I’ve ever met.

Even more than his decades of experience, that gift will help a President Obama with his ambitious domestic program as much as it will help in protecting America’s security.

Jim Rosapepe was U.S. ambassador to Romania from 1998 to 2001.