Donald Trump arrives in Britain tomorrow.  On Wednesday, he joins Theresa May, and leaders of NATO countries, at a commemoration in Southsea.  The Conservative leadership contest will therefore pause: why should the contenders make big announcements, and release names of supporters en masse, when media and voter attention will be elsewhere?

After the President leaves, and as the first ballot of MPs approaches during the week beginning next Sunday, the contest will pick up pace rapidly.  Until then, we will be left to ponder the question: will Trump’s effective endorsement of Boris Johnson help or harm the latter?

The President is unpopular with voters, according to YouGov, with an approval rating of 21 per cent and a disapproval one of 67 per cent.  Only 12 per cent have no view one way or the other.

None the less, the extent of his unpopularity can be exaggerated.  Trump is the seventh most popular politician in YouGov’s table, scoring better than Emmanuel Macron (10th), Vladimir Putin (11th), Jean-Claude Juncker (12th), Benjamin Netanyahu (11th), Leo Varadkar (19th) and Scott Morrison (24th).  But that last entry gives the game away a little.  The key point about the American President is that only 15 per cent of voters have heard of him. Ninety-name per cent have heard of Trump.

At one level, then, the President’s endorsement will do Johnson no good at all.  However, it represents only one of three dimensions of this peculiar contest.

For the leadership contenders must pitch to three audiences – Conservative MPs, Party members and voters as a whole.  The latter have been polled, as we’ve seen. Tory MPs haven’t been, as far as we know, but some will be very unenthusiastic indeed about the President.

Perhaps this site should survey Party members, because our sense is that they will be less hostile to the President than voters as a whole – partly because they will be less antipathetic to America than some; partly because the Republicans are a sister centre-right party…and partly because a larger slice of them than of voters as a whole will admire, like and support Trump.

And the President now says that Britain would get an especially good trade deal under a Johnson premiership, that could reasonably be expected to bump the latter’s support among activists up just a bit further.