WASHINGTON (NYTIMES) - America's global campaign to prevent its closest allies from using Huawei, the Chinese telecom giant, in the next generation of wireless networks has largely failed, with foreign leaders publicly rebuffing the US argument that the firm poses an unmanageable security threat.

Britain has already called the Trump administration's bluff, betting that officials would back away from their threat to cut off intelligence sharing with any country that used Huawei equipment in its network.

Apart from an angry phone call between US President Donald Trump and Prime Minister Boris Johnson, Britain appears to be paying no price for its decision to let Huawei into limited parts of its network, under what the British say will be rigorous surveillance.

Germany now appears ready to follow a similar path, despite an endless stream of cajoling and threats by Secretary of State Mike Pompeo, Defence Secretary Mark Esper and other US officials at a global security conference in Munich last weekend.

In public speeches and private conversations, Mr Pompeo and Mr Esper continued to hammer home the dangers of letting a Chinese firm into networks that control critical communications, saying it would give the Chinese government the ability to spy on - or, in times of conflict, turn off - those networks. The security risks are so severe, they warned, that the US would no longer be able to share intelligence with any country whose network uses Huawei.

"If countries choose to go the Huawei route," Mr Esper told reporters Saturday (Feb 16), "it could well jeopardise all the information sharing and intelligence sharing we have been talking about, and that could undermine the alliance, or at least our relationship with that country."

Yet officials sense their continued drumbeat of warnings is losing its punch in Europe, so the administration is shifting its approach. The US is now aiming to cripple Huawei by choking off its access to the American technology it needs and trying to cobble together a viable American-European alternative to compete with it.

The Huawei fight is just one part of a bigger US-China battle, as Washington tries to contain Beijing's influence and power and ensure that the world's second-largest economy does not come to dominate advanced industries that could give it an economic and military edge.

That includes the next-generation telecommunications networks that Huawei is building, known as 5G. Those superfast networks will control communications, critical infrastructure and, most worrying for US officials, the "Internet of Things" devices that are already controlling factories, autonomous vehicles and the day-to-day operations of military bases.

The US is also trying to limit China's access to US technology more broadly and is considering restricting sales of microchips, artificial intelligence, robotics and some types of advanced software, along with preventing tech companies from teaming up - or even sharing research - with Chinese firms.

But the effort to handicap Huawei has been complicated by the lack of an alternative to the company, which offers low-cost telecom equipment partially subsidised by the Chinese government.

Right now the only real competitors are Nokia and Ericsson, two European firms that claim they have deployed more 5G networks than Huawei, but are clearly struggling to match its prices or keep up with the Chinese firm's research and development.

That has sent the administration scrambling to present European and other nations with another option. Over the span of 10 days, Attorney-General William Barr, vice-president Mike Pence and other officials have offered differing US strategies to build a credible competitor to Huawei. Yet at times, they have contradicted one another's ideas, often in public.

In private meetings, Mr Trump has been urging American firms to get into the competition themselves. But the administration is deeply divided internally over whether the US needs to invest in the technology or leave the market to sort it out.

Mr Barr further confounded things with a speech this month where he called for US acquisition of Nokia and Ericsson "through American ownership of a controlling stake, either directly or through a consortium of private American and allied companies."

"We and our closest allies certainly need to be actively considering this approach," Mr Barr said.

US officials have gently walked back Mr Barr's comments. Asked about the prospect of a "controlling stake," Mr Robert Blair, an assistant to Mr Trump for international telecommunications policy, told The New York Times that "we are focused more on putting everyone in the tent than putting US taxpayer dollars in the midst."

Mr Pence, in remarks to CNBC, said the best response to Huawei was to free up airwaves for use in 5G networks operated by American carriers.

Huawei has proved increasingly effective at pushing back against the US. After US officials said last week that they had long ago found a "back door" that would allow the company to siphon information off any network, without American telecommunications firms knowing it, the company called it "impossible" and demanded evidence. But none has been declassified.

Mr Andy Purdy, a former homeland security official who now works for Huawei, said the company has suggested a way around security concerns by offering to license its technology "so the Americans or Europeans can build it themselves." The US has not responded to the offer, Mr Purdy said.

The fight over Huawei has put many European countries in a no-win position, forcing them to either rebuff a key intelligence ally's warnings and risk their key alliance, or alienate China, a critical trading partner.

Further complicating the decision is the lack of definitive US intelligence showing that Huawei has ever gained access to data that flows across its networks during the two decades it has provided telecommunications equipment to Europe.

Fear of Chinese retaliation has gripped Chancellor Angela Merkel of Germany and her government. While Germany's intelligence chiefs have largely joined the American assessment of Huawei's national security dangers, Mrs Merkel is focused on the effects on German exports to China, especially after Chinese officials have hinted that Volkswagen, BMW and Daimler, the maker of the Mercedes-Benz, would bear the brunt of retaliation.

"I have always been more concerned about the possibility of network manipulation," Mr Norbert Röttgen, the chairman of the German Parliament's foreign affairs committee, said at the Munich conference.

"You don't even have to actually take that step, if you control the network. The knowledge that you can is power in itself. How free would we really be in our choices with respect to protecting human rights and other issues if we know that the functioning of crucial parts of our economy depends on the goodwill of an external power?"

Yet European officials say Germany is likely to mirror Britain's decision to use Huawei and engage in strict monitoring. Germany, like Britain, is expected to keep Huawei out of the most sensitive parts of the telecom network but allow the firm to provide equipment and software for the radio networks that control cell towers and base stations around the country.

That decision will still be a huge loss for the US. Germany and Britain are America's closest intelligence-sharing partners, and both nations sit atop critical points along fibre-optic cables that are key to intercepting communications from Russia to the Middle East. US officials, including the National Security Agency, have expressed concern about the Chinese government's ability to infiltrate those communications.