One of the other main hopes No 10 aides have from the slightly unlikely rapport that has been seemingly struck up between the UK prime minister and US president is the hope that when Trump decides on any subsequent waves of tariffs, particularly towards Europe, the UK is spared.
Again, Starmer will want to try to understand what the US actually means by this – assuming there even is a settled idea in Washington – and to impress on Trump why cutting Europe adrift might come back to haunt the US.
A more formal post-Brexit trade deal would protect the UK even further, but given Trump’s take-no-prisoners negotiating style, plus pledges by Starmer’s government to not water down food safety regulations for US imports, this feels some way in the distance.
One of Trump’s perennial complaints, and one of the few where many European leaders might agree, is that the US shoulders too great a share of Nato’s burden, spending about 3.3% of its vast GDP on defence.
This might not be the most diplomatically dignified mission ever – Ed Davey, the leader of the Liberal Democrats, described it memorably as hoping to not catch the eye of the playground bully – but Starmer and his team will be painfully aware that tariffs on UK goods, and particularly a wider trade war, could wreak havoc on their primary goal of economic growth.
