The Conservatives want the next election to be about Brexit and Boris Johnson in Number 10. Labour want the election to be about stopping no deal and issues other than Brexit like the NHS, education and the climate change crisis. In terms of how this plays out in marginal seats, both sides have headaches.
So let’s look at each of these points in turn. Firstly, Boris Johnson wants a gladiatorial contest against Jeremy Corbyn for control of Number 10. Johnson leads Corbyn by 40 to 20 per cent for best Prime Minister. In response Corbyn's allies cite the revival of his leadership numbers in the 2017 election; but hoping for an improvement in the numbers isn’t as good as having a strong position to begin with.
Next, the Conservatives want this election to be about completing Brexit, and want to contrast this with Corbyn’s potential for undermining or ending Brexit altogether.