If Trump is serious about his foreign policy - or lack of it - then the answer must be: the UN
Since Donald Trump took office, a number of satirical videos have emerged, purportedly from European states vying to be 'second' to America's 'first'.
The German spoof cites the country's experience of walls. Luxembourg's boasts that it has a lot of money and "you know what, Mr President? You don't even have to pay taxes. None. Zero. Nada". And Switzerland's proclaims: "we also love to treat our women badly. Love it. We didn't let them vote until 1971."
But if Trump is serious about his foreign policy - or lack of it - he should be looking to strengthen diplomacy, particularly through the United Nations, the only organisation capable of tackling the major challenges facing the world. And American partners in Europe should be making this case vigorously. This is especially true for the UK, which sees itself as the closest US ally on the continent.
The Whitehouse's proposed cuts to UN funding are hardly surprising. Trump took aim at the organisation before his inauguration, tweeting that it was "just a club for people to get together, talk" (one of its most valuable functions) and that "things will be different after Jan 20th". A draft executive order on UN funding was prepared - and shelved - during his first week as president.
From across the pond, it appears that many Republicans, even those who opposed Mr Trump, are now exploiting his presidency to further red-meat issues, such as attacking the right to choose and the UN. While the American Sovereignty Restoration Act - a perennial fringe attempt to withdraw from the organisation - is as unlikely as ever to succeed, proposals supported by high-profile Republicans are more troubling.
Ted Cruz and Lindsey Graham, for example, have proposed defunding the UN in response to a Security Council resolution condemning Israel's violations of international law. That it passed only because the Obama administration chose not to veto it is conveniently forgotten. So too is the fact that millions of people would suffer as a result. In the words of former presidential candidate Rick Santorum, this "opportunity for those of us who are very anti-UN" to "deconstruct it" is simply too good.
Yet despite longstanding hostility to the UN, the Whitehouse budget is likely to encounter opposition in Congress. Even if it doesn't succeed, though, it is deeply concerning, implying a failure to understand the UN's value to the US.
The UN is at the centre of the rules-based international order that the US has built since the Second World War. It is structured in a way that cements American power and inoculates the country against global power shifts. As former US ambassador Susan Rice memorably put it: the Security Council can't even issue a press release without America's blessing.
Like its allies in Europe, US administrations have always acknowledged, albeit more reluctantly at times, the UN's role in furthering their interests. After 9/11, G.W. Bush may have sought to justify "coalitions of the willing", but he also reaffirmed US commitment to the UN, noting that "no nation can build a safer, better world alone". The invasion of Iraq without UN blessing ended up harming the US more than the organisation.
If Trump truly wants to put "America first" and play a less active global role, the UN will be crucial in picking up the slack in terms of promoting stability. Europe is going through a period of turmoil, with challenges from within - political and economic - and from without, notably a more adventurous Russia. The major emerging economies meanwhile, with the exception of China, seem disinclined to play global policeman, humanitarian or peace broker.
The UN is also a vital tool for furthering Trump's foreign policy priorities, by strengthening international efforts to counter terrorism and by creating the conditions for trade to flourish. It also provides a mechanism for US allies, in his words, "to take a direct and meaningful role in both strategic and military operations, and pay their fair share of the cost".
And the UN is cheap. Its interventions are far more cost-effective, and generally more successful, than those of the US. The UN's annual peacekeeping budget, covering 16 operations on four continents, is roughly equivalent to what the US spent a month in Afghanistan at the height of the conflict.
Other countries provide the lion's share - over 80% - of the organisation's shoestring regular budget (which, by the way, is a sixth of what Americans spent on carry-out pizza in 2015). US UN funding represents just 0.1 per cent of the federal budget and is generally supported by the American public.
Today, the UN is needed more than ever. The convergence of multiple crises has stretched the post-1945 international system to breaking point, threatening to reverse the gains of the past 70 years. Yet instead of increased engagement with the UN, national outlooks are narrowing. More countries are seeking to put themselves "first", ignoring the reality that the line between national and global interests has blurred. In the UK, too, internationalism is no longer the default position.
While Obama's record at the UN was far from perfect (the US continued to shield its allies from criticism and oppose proposals it disliked), the past eight years showed just how much constructive US engagement can achieve, from helping to secure the Paris climate agreement to negotiating the Iran nuclear deal. And in Secretary-General António Guterres, the US has a strong partner in areas of interest, such counter-terrorism, management reform and tackling sexual abuse by UN peacekeepers.
To put America first, Mr Trump must put the UN second. Channeling the far-sighted leadership of UN founding father Franklin D. Roosevelt is the best way to make America great again.