WASHINGTON — When the advisers tapped by Senator Obama to find a vice president met with lawmakers on Capitol Hill, one name that leaked out was that of a former NATO commander, General James Jones.

But yesterday, as the presumptive Democratic nominee held briefings in Washington with dozens of military and foreign policy advisers, General Jones was not there. Instead, he was in Missouri, sitting on an energy security panel convened by Mr. Obama’s Republican rival, Senator McCain, who praised him as “a great friend and a great patriot.”

That General Jones would be mentioned as a potential running mate for one party nominee and participating in a campaign event of the other befits the reputation forged by a man known equally for his diplomatic skills and his military acumen, foreign policy analysts said yesterday.

“I had no idea whether he was a Democrat or a Republican. All I know is he was respected on both sides,” a former Pentagon colleague of General Jones’s who now heads the Center for a New American Security, Kurt Campbell, said in an interview.

A native of Kansas City, Mo., and a Vietnam veteran, General Jones, 64, served between 2003 and 2006 as the supreme allied commander of NATO forces in Europe after having served as the commandant of the Marine Corps under presidents Clinton and Bush.

He spent much of his childhood in France before returning to attend Georgetown University, and he still speaks fluent French, said Mr. Campbell, a former assistant defense secretary who noted that unlike many military officers, General Jones is “very comfortable in cosmopolitan settings.”

“The hardest thing to do is to find that officer who is comfortable not only on the battlefield but in the more treacherous halls of diplomacy, and he is that guy,” Mr. Campbell said.

Standing well over 6 feet, General Jones cuts an imposing figure, but he is described as congenial and thoughtful. One Democratic Senate aide said he was known to avoid theatrics during congressional testimony and largely epitomized the Theodore Roosevelt mantra of “speaking softly and carrying a big stick.”

The chief obstacle to General Jones’s selection is likely his near-total lack of familiarity among voters nationwide, but the benefits to an Obama-Jones ticket are also clear: As a potential running mate to a man with little foreign policy experience, General Jones could signal a reassuring presence without upstaging the headline act.

“There’s no one like him in central casting,” Mr. Campbell said. “He is big, handsome, extremely dominating, but also gracious to a fault.”

Since retiring in 2007 after 40 years in the Marines, General Jones has been active in a variety of policy issues. He led a commission assessing the strength of Iraqi military and police forces, drawing pointed questions both from Mr. McCain and Senator Clinton at a congressional hearing when he recommended that America reduce its “footprint” in Iraq but warned against a firm withdrawal deadline and a precipitous pullout of troops.

In November, Secretary of State Rice named him as a special envoy for Middle East security.

He sits on the board of Chevron and has also run the Institute for 21st Century Energy, a Washington-based think tank started last year by the U.S. Chamber of Commerce. It was in that capacity that General Jones appeared yesterday in Springfield, Mo., where he spoke on a panel organized for Mr. McCain’s town hall meeting.

General Jones offered no endorsement of Mr. McCain, nor did he specifically address the Arizona senator’s call this week to lift a federal ban on offshore oil drilling. He avoided partisan talk altogether, urging America to take a greater leadership role in the global energy crisis by developing a long-term solution that would “transcend election cycles.”

“This issue is not the property of any particular political party. It is the property of all Americans,” General Jones said. “We have delayed taking on this problem long enough.”

A spokesman for the Obama campaign said General Jones was not invited to the Illinois senator’s foreign policy meetings in Washington yesterday. The presumptive Democratic nominee met separately with a campaign working group he formed on national security and with more than 40 military leaders, many of whom had supported Mrs. Clinton during the primaries.

The panel included others floated as potential running mates, such as a former Georgia senator, Sam Nunn, and another former NATO commander, General Wesley Clark.

General Jones’s long relationship with Mr. McCain — the two served together as military liaisons to the Senate nearly three decades ago — is one reason he is considered a long shot for a spot on the Obama ticket, despite the buzz coming out of meetings that Mr. Obama’s advisers held with Democratic lawmakers earlier this month.

Another is that, despite the general’s impressive military résumé and a “very solid” reputation among both Democratic and Republican leaders, few can point to a career-defining achievement or legacy, a senior foreign policy fellow at the Brookings Institution, Michael O’Hanlon, said.

“He wouldn’t have the star power of a Colin Powell or even a Norman Schwarzkopf for that matter, because no one really knows who he is among the general public, and even a lot of defense specialists wouldn’t be able to say a lot about what he actually accomplished,” he said.

While General Jones led NATO during its involvement in the war in Afghanistan, which has drawn less criticism than the Iraq conflict, “he was not the guy coming up with the war plan,” Mr. O’Hanlon said.