Gov. Scott Walker sat at England's most prestigious foreign policy think tank, a map of the world behind him, the eyes of Europe's intelligentsia in front of him, and talked about cheese.
Colby cheddar, to be precise.
"We say: Let the best cheese win," the Wisconsin Republican told the audience, his hands raised in triumph.
The moment in February crystallized one of Walker's greatest challenges as he readies himself for a presidential bid. Among top-tier candidates, he has the least experience with the rest of the world and may have the most to prove to voters.
Since that trip to London, Walker has scrambled to get a cram course in world politics and national security. His tax-exempt political committee has hired foreign policy staff. He attends current-events briefings nearly every day. He has traveled to the Texas border, Europe, the Middle East and Canada. He's met with scholars from conservative think tanks.
Among the 16 Republicans seeking the party's presidential nomination, Walker, who plans to formally announce his candidacy Monday, has arguably done the most so far to excite conservative voters. He has established himself as a favorite in Iowa, scene of the campaign's first nominating contest, and as a strong rival to former Florida Gov. Jeb Bush, Sen. Marco Rubio and other leading figures in the party.
But his lack of foreign policy credentials could set him up for the sort of problems that bedeviled another conservative governor, Sarah Palin, seven years ago.
Kori Schake, a research fellow at the Hoover Institution who helped prepare Palin when she was chosen as John McCain's running mate in 2008, said the challenges for foreign policy neophytes like Walker would multiply as the campaign moves on.
Palin quickly mastered 100 flashcards designed to give her one smart thing to say on any topic that might arise, Schake said. "She surged at moments when she anticipated it," Schake added. But she noted that when Palin overstated her command of the facts or inflated her role as Alaska governor, she "said things that called into question both her knowledge and her judgment."
Schake said she was impressed at how Walker had rebounded from some of his earlier stumbles. But all the candidates will eventually need to articulate a foreign policy vision "beyond criticism of Obama's failures," she said.
Preparing the candidate for that moment is the goal of the intensive schooling that Walker has been undergoing.
The governor of a relatively homogenous state who is less than five years removed from his days as Milwaukee County executive, Walker has never worked in the federal government or the military. He would be a rare serious candidate in modern presidential politics who has not completed college, and would be the first president since Harry Truman without a college degree were he to win.
His strength as a primary candidate — an all-consuming battle to weaken his state's public employee unions that raised his national profile — has crowded out other issues.
"If I was talking about Iraq, I would not have called Scott Walker," said Mark Belling, a conservative radio host in Milwaukee who has known Walker for more than two decades.
Walker has tried to engage Obama aggressively on foreign policy — criticizing him in speeches, news releases and interviews -- while avoiding situations that could put him out of his depth or force him to make detailed policy commitments.
In speeches to Republican activists, he refers to national security as "safety" — an effort to make geopolitics feel personal — and says it has risen "to the top of [his] list of priorities."
His London speech drew headlines for his refusal to answer a question about whether he believed in evolution. But inside the room, many were baffled that he refused to address questions about foreign affairs that many before him had answered. Walker cited a belief that he should not comment on American policy while on foreign soil.
"It was like a car crash," said James D. Boys, a scholar in the audience and author of "Clinton's Grand Strategy," whose own question went unanswered. "You don't come to Chatham House to talk about Wisconsin and Milwaukee dairy products."
Those who have advised and spoken with Walker say he now understands the challenge and is prepared to meet it.
"On foreign policy, there's always a lot to learn," said Rep. Paul D. Ryan, a Wisconsin Republican who has long been close with Walker and served as his party's nominee for vice president in 2012. "You have your set of principles, your worldview, and then you refine as you go."
But Ryan, like others interviewed for this story, was reluctant to describe Walker's worldview too specifically. The public record also shows little about the candidate's views on most foreign policy issues. Until recently, when he began exploring a presidential run, Walker rarely expounded on immigration, Syria or the Iran nuclear deal.
"Those are the first times I've ever really heard him talk about those issues because those are the first times he's really been asked," Belling said.
Ryan said that after the Sept. 11 attacks, Walker, then a member of the state Legislature, had asked a lot of questions about Iraq and Afghanistan, showing a natural curiosity. Walker did not offer an opinion of the U.S. invasions before Ryan, already in Congress, cast his votes to authorize force, Ryan said.
"We don't tell each other what to do," he added.
Ryan and others say Walker models his ideas around President Reagan, his political hero, and believes projecting resolve will protect U.S. interests before crises erupt.
"He's obviously not the only one to do that," said Jim Talent, a former Missouri senator who advised Mitt Romney on foreign policy and is now a top advisor to Walker. He added that Reagan's "was the most successful foreign policy presidency, in the experience of people around his age."
Walker has also tried, not always successfully, to link Reagan's philosophy of peace through strength to his experience as a governor who took on labor unions. He has said that former Secretary of State George P. Shultz told him that Reagan's firing of the air traffic controllers who went on strike early in his tenure was his most important foreign policy decision, because it demonstrated resolve to foreign leaders.
But Walker's first effort to make such a comparison publicly drew ridicule when he was asked how he would respond to Islamic State militants and compared that fight to his confrontation with Wisconsin's labor movement.
"If I can take on 100,000 protesters, I can do the same across the world," he said.
Walker's recent trip to Israel showed more caution. He met privately with Prime Minister Benjamin Netanyahu, U.S. Ambassador Dan Shapiro and several Israeli government officials, but took no questions from the foreign or domestic press.
Elliott Abrams, who served in the Reagan and George W. Bush administrations, attended several meetings on the Israel trip as an informal advisor to Walker. He said the governor came with well-prepared staff memos but offered few opinions.
"He tried to get the person he was meeting with to talk most of the time," Abrams said. "His questions were not soliloquies. They were real questions."
Abrams, who has met with several current and potential candidates, said Walker's command of foreign policy improved greatly between February, when he first met with him, and when they met in Israel.
"As a generalization, the senators are better prepared on foreign policy than the governors," Abrams said. "The question really is, for Republicans — beyond the personalities involved — do you want a governor who has proven executive experience? ... Do you want a senator who's fully informed about foreign affairs?"