This visit from the UK's David Cameron to the US reaffirms both countries' long-term commitment to supporting Ukraine. Ukraine's success in this conflict is vital for American and European security. Russia cannot be allowed to succeed as it would only to serve to embolden more land-grabs from other autocratic countries.
It's tricky to see how Cameron could effectively enact any level of diplomacy with the US over Ukraine if the UK wants an all out victory for the nation. Trump has only just expressed his support for a rapid peace plan, involving Kyiv surrendering territory to Moscow. Many Americans have grown skeptical of the amount of tax payer money being sunk into this conflict and care more about a practical conclusion than proving a point on the world stage.