Wisconsin Gov. Scott Walker leaves a meeting in London on Wednesday. (Tim Ireland/AP)

— Wisconsin Gov. Scott Walker’s appearance Wednesday evening before a prestigious think tank here was an opportunity for the likely presidential candidate to demonstrate a fluency in foreign affairs.

Instead, the Republican governor went to great lengths to avoid commenting on pressing global issues such as the Islamic State and the unrest in Ukraine — even ducking a query about whether he believes in evolution — in a performance that left many in the packed audience befuddled.

“I’m going to punt on that one as well,” Walker said in response to a question about whether he was comfortable with the idea of evolution, much to the incredulity of the BBC’s Justin Webb, who moderated the event.

“That’s a question that a politician shouldn’t be involved in one way or another,” Walker added.

Later, Walker tweeted that “both science & my faith dictate my belief that we are created by God. I believe faith & science are compatible, & go hand in hand.”

The speech was Walker’s only scheduled public event during his four-day visit to London, which wraps up Friday.

The trip was billed as as a low-key trade mission, aimed at boosting ties between Wisconsin and the United Kingdom. But with Walker surging in the fast-moving race for the GOP presidential nomination, the visit offered a chance to accrue some credentials on international issues.

Instead, he played it cautious, declining to outline a foreign policy vision or even share his take on specific matters, such as the United Kingdom’s role in the European Union.

He declined to say whether Britain and the United States were doing enough in its fight against Islamic State extremists, saying it was not an appropriate subject to address while on a trade mission.

“That’s certainly something I will answer in the United States in the future,” he said.

“Maybe it is a bit old-fashioned,” Walker added. But he said that no matter what his opinion of President Obama, “I don’t think it’s wise to undermine the president of your own country” while abroad.

“When you’re in a foreign country, to me, I defer to the president even though I don’t always believe in the same things as he does politically,” he said.

Later, to a questioner who asked whether the United States should arm Ukraine against Russia-backed rebels, Walker said, “I have an opinion on that,” but added: “I just don’t think you talk about foreign policy when you’re on foreign soil.”

At Wednesday’s event, Walker did have a lot to say about the “special relationship” between the United States and the United Kingdom, heralding the countries’ bond at least eight times.

And then there was cheese — a subject he cited repeatedly while discussing his state’s economy. If Wisconsin were a country, Walker declared, “it would rank fourth in world for cheese production,” just above Italy.

His restrained performance was a marked contrast with the rousing speech Walker delivered to conservative activists in Iowa last month, where he drew the audience to their feet. A spate of early polls also show him at the top of the GOP pack in key states such as Iowa and New Hampshire.

But his London outing underscored the challenge Walker faces in demonstrating his fluency in world issues amid a crowded pack of potential candidates that includes foreign policy hawks such as Sen. Marco Rubio of Florida and Sen. Ted Cruz of Texas.

During his own visit to London last week, New Jersey Gov. Chris Christie — also a potential GOP contender in 2016 — criticized Obama for his handling of the Islamic State group, but later stumbled into controversy by suggesting childhood vaccinations should be optional.

Walker scolded the media Wednesday for pouncing on the comment by “my friend” Christie, “even though that probably wasn’t the most substantive thing he was talking about here.”

Walker, for his part, worked hard not to be glaring. He had a private meeting with David Cameron, the British prime minister, and met with Britain’s treasury chief George Osborne, business executives, and alumni from Wisconsin universities.

During his speech at Chatham House, Walker said he hoped to return to the U.K. to visit the hometown of his Welsh ancestors and noted that he visited the resting place of Margaret Thatcher to “pay respects to your Iron Lady.” He quoted Churchill.

The governor also offered a hint of some of the themes that are likely to undergird his expected candidacy. He cast himself as a reformer, decried a federal government that he said has “taken more and more power away from the states.”

Benno Zogg, a 25-year-old security studies student at King’s College London who was in the audience, said that Walker’s address “sounded very much like a presidential candidate speech you see on television.”

But “on foreign policy, he clearly has some weaknesses,” he added. “We saw today he was avoiding pretty much anything on it.”

Gold reported from Washington.