Well that's highly suspicious. It must be a conspiracy Obviously another attempt to deny the Republicans' democracy.
(I haven't worked out what you meant yet, but what I said is what it must be....)
He has started some sort of action accusing the UK of interfering with US elections even though collaboration between our and their parties is normal and not illegal. Sounds like it probably wont get anywhere but still a useful idea to use.
The only way he can make the claim is to assume that Labour are providing money to Harris, They aren't Apart from that it is legal on both sides of the pond and known to go on with like minded parties.