There are two things here; one is the continued attraction of the US's well funded rightwing infrastructure. Dan Hannan, being an MEP, doesn't have to publish very much in the way of a declaration of interest - in fact, in the past he's been pretty strident about this. At the same time, hard-right politicians throughout Europe are well known for funding their party organisations out of EP expenses, and Hannan is doing the reverse; rather than using EP funds for party purposes, he's using his status as an MEP to go on the speaking circuit in the States and bask in wingnut welfare.
The second is that the US political circuit is being used as a sort of substitute for British politics here. Hannan at least thought he could say things in the States that would get him in a good deal of trouble in either Westminster or Brussels; intervening in US politics is a way of positioning yourself in Tory internal politics, without showing your hand too much. To be publicly rightwing enough that you want to abolish the NHS is not career positive if it gets into the papers; he seems to have thought that the public wouldn't notice as long as it happened beyond the seas, but that the sort of Tory constituency associations that could get him a Michael Gove-like seat for life would notice.
Interestingly, it seems to be the case that Conservative Party politics operates in a trans-atlantic world akin to "the isles" in recent British historiography - up until the 18th century or thereabouts, it was possible to play off Scotland or Ireland against London effectively, Scottish and Irish armies were deployed to England during the civil war as (mostly) English ones went the other way. Similarly, Conrad Black imagined himself kingmaker from Toronto. It's happened before, too - here's a fascinating letter about Saskatchewan's NHS-like system, which faced a barrage of redbaiting and was eventually set up with the assistance of volunteers from the UK.
It goes beyond the mere intergovernmental alliance; tellingly, Atlantic Bridge in its current form was set up in 2003 to drum up support for the Iraq war, and it is chaired by Dr Liam Fox MP, one of the Tories who spent 2002-2003 arguing that the Blair government was not sucking up to the Americans enough. I've argued before that the Decent Left movement has succeeded, in that it's found a home in the Conservative Party through figures like Michael Gove; Hannan is probably too much of a tribal Tory to be considered Decent, despite being close to Gove and wired up to the Iraq noise machine.
However, all this relies on the Atlantic as a semi-permeable membrane. It is crucially important that only the bits of your westward enterprise that you want arrive back in London. Access to the bridge must be strictly controlled. This appears to be what went wrong with Hannan's propaganda tour; when the Guardian is one of the most read newspapers in the US, it's much harder to achieve compartmentalisation, and the instigators of the #welovethenhs Twitter drive blew the seal so comprehensively that they forced David Cameron to join up and very publicly disown Hannan.
Marked out as a loose cannon, his chances of being parachuted into the Commons must now be considered poor. So you can expect a lot more wingnut chum from him, as he steps up his campaign for a sinecure at the Heritage Foundation.
Chris Dillow points out that perhaps, if we were to do it all over again, we might not design the NHS the same way. Well, maybe not. The really interesting bit, however, and the conclusive evidence that this was a content-free piece of Tory internal politics is that Hannan and Gove's own proposals are essentially identical to Obama's.
Both books call for the NHS to be replaced by a new system of health provision in which people would pay money into personal health accounts, which they could then use to shop around for care from public and private providers. Those who could not afford to save enough would be funded by the state.So, personal insurance, with a public sector option, and Medicare/Medicaid benefits. West of 30 degrees, he agrees with people who think this is equivalent to Nazism; east of 30 degrees, he thinks it's genius. The real content here is that Hannan wants to be considered a maximum rightist in two different political systems, and doesn't give a damn for the actual content of anything he says.