London (CNN) The silence from other world leaders in condemning US President Donald Trump's most recent racist comments has been deafening . There have been remarks from Canada's Prime Minister, Justin Trudeau, who said: "That's not how we do things in Canada," and that a "Canadian is a Canadian." The outgoing British Prime Minister, Theresa May, said that Trump's comments were "completely unacceptable."

Otherwise, the world, it seems, is turning a blind eye to the most powerful office in the world being used to make overtly racist statements.

Why is this the case? It's not as though the international community is incapable of coordinating a response when it feels the need to. Just last week, 22 nations signed a letter to the UN condemning China's mass detention of Uyghur and other minorities.

He also described the four congresswomen of color as "hate-filled extremists" and repeated his line from the weekend saying that "if they don't like it, let them leave."

In an instant, the wild, inaccurate ranting of a man under attack morphed to something more chilling. Trump's supporters chanted "Send her back!" in response to comments aimed at one of the women, the Somalia-born Rep. Ilhan Omar, a naturalized US citizen. Trump made no attempt to stop the words being chanted towards an elected politician and American citizen.

JUST WATCHED Lemon: Will these people chanting be proud in 10 years? Replay More Videos ... MUST WATCH Lemon: Will these people chanting be proud in 10 years? 06:42

In the past, world leaders have managed to get on the same page when they agreed a message needed to be sent to the President -- think Iran, trade and climate change.

Perhaps these foreign leaders feel this is a domestic American issue. To those of us observing from outside the country, it seems obvious that this sudden escalation in rhetoric is aimed squarely at Trump's base, and has everything to do with the US entering its election cycle. So perhaps world leaders think it's none of their business.

Or perhaps, as CNN's Nic Robertson suggested earlier this week , it's because the international community feels it can only push the world's hyperpower so far.

America is everyone's biggest sibling. It underpins the security, economic stability and democratic confidence of so many nations around the world. It is the largest contributor to NATO and has the world's most comprehensive intelligence networks. Bluntly, every nation that has been able to call America an ally has benefited from its security blanket.

Trump's continued trampling on the dignity of the office is going to give America's allies a lot to think about. Right now, the President is still globally powerful enough to push smaller nations around. Just look at the way some senior British politicians fell in line after Trump attacked Kim Darroch, the UK's ambassador to DC. But will there ever be a point when enough is enough?

As Brian Klaas, assistant professor in global politics at University College London, points out, it could soon become "much harder for foreign leaders to sell their own population on the idea that their alliance with the United States is based on shared values." Right now, that seems a long way off. But should Trump win a second term in office, Klaas believes "there will come a time when negative public opinion toward the US forces leaders in those countries to downgrade its strategic relationship with America."

In the short-term, this leaves foreign leaders in a tight spot. Without knowing how the US election will go, it's easy to see why silence is the best option. But as Leslie Vinjamuri, head of the US and the Americas program at Chatham House, explains, this short-term strategy could lead to long-term headaches:

"The future of America is bound to be liberal, democratic and inclusive, but not absent (of) ongoing vigilance by leaders at home and also abroad to safeguard these values. European leaders who fail to call out racist language send a signal to their own people, also, about their future. Choosing to be silent in the face of Trump's racist language is choosing to be on the wrong side of history. It is a miscalculation and also a mistake."

It's not hard to see how impossible all of this looks for international leaders. Do you provoke a man who has demonstrated time and again that he is happy to lash out at people who disagree with him? Or do you gamble that at some point, the US will return to previous form?

During the previous US election, several prominent world leaders came out strongly against things Trump said on his campaign. It will be telling so see how many have the courage to do the same over the next 18 months.