Wisconsin Gov. Scott Walker has been in London this week as part of a trade mission widely seen as a prelude to a possible 2016 presidential run. But during a Wednesday appearance at the Chatham House think tank, he firmly declined to address a multitude of subjects:

*United Kingdom membership in the European Union.

*The fight against the Islamic State.

*Whether the U.S. should arm Ukraine against Russia-backed rebels.

*His general foreign policy vision.

*Whether he believes in evolution.

“I’m going to punt on that one as well,” Walker said in response to the latter, much to the incredulity of Justin Webb of BBC Radio 4, who served as moderator at Walker's sole public appearance in the four-day trip. “That’s a question that a politician shouldn’t be involved in one way or another.”

The likely Republican presidential candidate tried valiantly to avoid weighing in on any controversial issues during his hour-long appearance -- particularly when it came to international affairs.

“I’m not trying to skirt your question,” Walker said at one point, adding that “for me, commenting on foreign policy or economic policy in a country where you’re a visitor is not the polite thing.”

Walker’s cautious approach came on the heels of a tumultuous visit to London by New Jersey Gov. Chris Christie, one of his expected rivals for the GOP nomination in 2016, who generated a storm of criticism by suggesting parents should have a choice about vaccinating their children – a comment his office quickly walked back.

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

“That’s a good example where there’s this almost magnetic thing where they go to whatever is the most glaring,” he said.

For his part, the Wisconsin governor strove to avoid generating any such headlines.

On the question of whether Britain and the U.S. should do more to contain the Islamic State, Walker said that because he was on a trade mission, he did not think it was appropriate for him to address the subject.

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

“Maybe it is a bit old fashioned,” Walker acknowledged. 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” on foreign soil.

Later, to a questioner who asked about arming Ukraine, the governor said, “I have an opinion on that,” but said, “I just don’t think you talk about foreign policy when you’re on foreign soil.”

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 in noting his state’s strong trade economy.

If Wisconsin were a country, Walker declared, “it would rank fourth in world for cheese production,” just above Italy.