British prime ministers do not, as a matter of protocol, express preferred outcomes in US elections. But there is no convention limiting the number of times the question can be asked. It won’t go away while Donald Trump is a contender for the White House.
A second Trump term can’t be brushed aside as the kind of hypothetical scenario on which leaders routinely withhold comment. Nor can it be cordoned off as foreign policy, which rarely influences UK general elections.
