WASHINGTON The requisites for a secretary of state, along with intelligence and judgment, are a knowledge of foreign policy, an understanding of domestic politics, and, ideally, first-hand experience of what President Dwight D. Eisenhower called the “brutality and stupidity” of war.

Sen. John Kerry, who was tapped by President Barack Obama to succeed Hillary Clinton, checks off all those boxes. He has been an engaged diplomat, a successful politician with gravitas and a decorated combat veteran.

Much of his 28-year Senate career has focused on national security. He was among the few young Americans of privilege who fought in Vietnam. Like Clinton, though unlike most modern-day secretaries of state, he understands how U.S. politics affects foreign policy on issues from the Middle East to China. The 69-year-old Massachusetts Democrat has won six statewide races. He knows how Washington works.

As the Democratic nominee in 2004, Kerry lost a close race to President George W. Bush. That experience is central to the Kerry of today. A tough public rejection lessens many politicians, who become obsessed with might-have-beens. After a fairly short pout, Kerry bounced back to become a more formidable senator.

The issue that bedeviled him throughout that campaign was his vote for the Iraq War; his staff convinced him that to oppose it in 2002 would have been suicidal to his presidential ambitions. His attempts to gloss over that decision during the presidential race backfired.

He has supported Obama’s policies on Iraq and Afghanistan and will be a voice for negotiation with Iran. On most issues, his views are very much in sync with the president’s. On occasion, the administration has followed the Kerry approach: He pressured a reluctant White House to impose a no-fly zone to topple the Libyan dictator Moammar Gadhafi and to call for the removal of President Hosni Mubarak in Egypt.

Kerry has met many world leaders, developing a reputation as both a good listener and analyst; an exception was his sense not too long ago that the U.S. could work with the Syrian dictator Bashar Assad.

Kerry has been the activist chairman of the Senate Foreign Relations Committee since 2009, fashioning bipartisan support for measures such as one that shifted U.S. aid to Pakistan from predominantly military support to include more civil assistance.

In 2010, prospects for a nuclear arms-reduction treaty were considered dim; Republicans were strongly opposed and had little interest in giving Obama another victory. Kerry persevered, ultimately picking up enough Republican support to comfortably clear the two-thirds vote required for ratification.

He has played an important troubleshooting role for the Obama administration in Afghanistan and Pakistan, where, observers say, he deftly handled difficult leaders. Two decades earlier, he and Sen. John McCain, a Republican from Arizona and a fellow Vietnam War veteran, orchestrated the normalization of relations with Vietnam.

The son of a Foreign Service officer, Kerry will fit in comfortably at the State Department. He will encounter challenges; inevitably, he will be compared to Hillary Clinton, a rock star around the globe.

Moreover, as with Clinton, there will be carping by some anonymous aides in the White House who believe the secretary of state should travel the world while they make policy. The Kerry-Obama relationship is good. It was Kerry, as the party’s nominee in 2004, who picked Obama as the convention keynote speaker, his debut on the national stage. They aren’t close; this president doesn’t forge close relations with fellow politicians.

Kerry tends to play things close to the vest, a better trait for a senator than for the country’s top diplomat.

And he still is seen as an elitist, a bit awkward and aloof, a rap that Bush pinned on him in 2004 that has some merit.

Yet those who believe he’s a patrician stiff should talk to Brendan O’Donnell, who has been learning-disabled his whole life and has been on Kerry’s Boston staff for almost a decade.

“He’s a great guy and he’s always willing to fight for you,” O’Donnell says.