ENNISKILLEN, NORTHERN IRELAND - JUNE 17:  Britain's Prime Minister David Cameron (L) and US President Barack Obama (R) wave as they arrive at the G8 venue of Lough Erne on June 17, 2013 in Enniskillen, Northern Ireland. The two day G8 summit, hosted by UK Prime Minister David Cameron, is being held in Northern Ireland for the first time. Leaders from the G8 nations have gathered to discuss numerous topics with the situation in Syria expected to dominate the talks.  (Photo by Matt Cardy/Getty Images)
Other times Obama gave advice to Britain
01:52 - Source: CNN
Aerzen, Germany CNN  — 

It was a time for expressing “opinions” among friends – in a big way. Even on a referendum that is not in one’s own country.

Such was the stance of the White House as President Barack Obama arrived in the U.K., fully willing to offer his views – if asked, mind you – to America’s closest allies, on the Brexit. That’s the momentous vote the British people will take on June 23, deciding whether or not to stay in the European Union.

But when European leaders were then asked to return the favor, and offer their “opinions” on the ever-controversial rhetoric of Donald Trump – both British Prime Minister David Cameron and German Chancellor Angela Merkel just as emphatically and surprisingly punted.

“I’ve made some comments in recent weeks and months. I don’t think now is a moment to add to them or subtract from them,” Cameron said during a news conference, drawing laughter from the crowd.

He added: “You always look on at the U.S. elections in awe of the scale of the process and the length of the process, and I marvel at anyone who is left standing at the end of it.”

And Merkel two days later was even more terse.

“I concentrate on the task ahead for 2016. I’m quite busy with that, thank you very much. And I’m looking with great interest at the American election campaign,” she said.

This, a few months after Trump branded Merkel’s acceptance of more than a million refugees “insane,” predicted riots and called her leadership “catastrophic.”

But both nations have not been so shy in expressing their derision of the American political rhetoric before, making their silence now all the more striking.

Back in December, Cameron called Trump’s idea to temporary ban all Muslims from entering the United States “divisive, stupid and wrong.”

A month later, the British Parliament debated a plan to ban Trump from entering the U.K. based on what some considered his “hate speech” and “unacceptable behavior,” but didn’t end up taking a vote.

“If he came to visit our country, I think he would unite us against him,” Cameron had said.

The prime minister has also opined that Trump’s words are making it harder to defeat ISIS.

Merkel, previously wading into 2016, has praised Hillary Clinton. And the German vice chancellor weighed in just last month on Trump, lumping him in with “right-wing populists” in Europe.

“(He is) not only a threat to peace and social cohesion, but also to economic development,” she had said.

CNN asked 10 Downing Street why Cameron was so reticent to take his chance to riff on American politics Friday, but the press office, too, politely declined comment.