As much as America would like to think their laws apply across the globe, they don't actually have jurisdiction over you. There's nothing they can do to prevent you from talking about the campaign.

They do have jurisdiction over the candidate and campaign you endorse, though. If you contacted your candidate and offered them money or services in the hope that they could use your help to get elected, and they accepted your offer they would be guilty. You wouldn't be.

Unfortunately, it seems like a fairly impotent law if all you have to do as a foreign national with an interest in the election is to support a candidate without their endorsement.

> As much as America would like to think their laws apply across the globe, they don't actually have jurisdiction over you.

You might want to check with Humberto Álvarez-Machaín (acquitted, sure, but not because the law didn't apply to him) or Manuel Noriega about that.

Or Howard Marks in the book Mr Nice tells a bit about his thinking the US had no power over him and then, oops.

But I could, for instance, buy advertisements in support of my favoured candidate?

I guess not on US TV or US billboards since they're under the control of the US. But if I buy ads on the internet that just happen to be seen by US citizens there's nothing the US can do about it, right?