Nigel is a notorious racist and lush.

Last night he was in Texas.
He's bailed on three events one of which was in Oregon.

Maybe it's crowd sizes and energy in fully red states that he wants since it will be on national TV. That's all I can figure.

Or does the prohibition on foreign support relate only to financial contributions?

Farage was there officially to give the story of Brexit, though he certainly took the opportunity to kiss the Trump Rump. You can keep him, as far as I'm concerned.

Liam Fox, British MP, former Defence Secretary and now Secretary for International Trade, was active in the Romney campaign (he was a backbencher then, but still an MP). I was amazed that it was permitted.

This does indicate that for a certain group, Brexit is all about promoting fascism, not about national sovereignty. Trump and Farage seem to find nothing wrong with a politician of one country getting involved in the elections in another; and in any case, it is slightly puzzling why the Trump voter base would be all that interested in Brexit as such: why should they care so much if a country thousands of miles away from them chooses to fuck itself up by withdrawing from the nearest major trading organization? Some may be confusing the EU with the UN, about which I gather the American Right has a range of conspiracy theories; but I suspect a lot of is 'oh how lovely; this British guy hates immigrants and liberals just as much as we do!'