LM must sometimes be tearing their collective hair out at some of the blowhards on Capitol Hill, however workshare too is a problem.
But technology is not quite a one way street, the R/R input already mentioned, plus BAE have provided
ALM Antillean Airlines (Netherlands Antilles)">LM with advice and technology on production, based heavily on their own experience with advanced production techniques on the Eurofighter.
Even the UK, who have been on board from the very start, investing a couple of billion $, have some issues.
The UK branch of RAND have investigated whether a UK production line should be set up, I don't recall seeing their conclusions however.
I'd say it's important, UK F-35's will carry different weapons for a start, it's worth remembering that the UK is so far the only firm export customer so far, with 150 F-35B's for RAF/RN.
If a further batch of say F-35C's are procured, (to partly replace Tornado
GR.4s from 2015 onwards, alongside probably Batch 3 Typhoons and certainly UCAVs), a UK line might become even more attractive, major components are already in production at BAE plants now anyway.
UK has been involved with
LO technology for a long time, dating back to co-operation as far back as the late 1950's, only de-classified in more recent times.
Unknown to most, V-Bombers had radar absorbent material added to some surfaces, more recently, leading edges of RAF Tornados and Jaguars got the same treatment just before the 1991 Gulf War, en-masse.
UK pilots flew F-117's on night-time flights from RAF Binbrook well before the 1988 unveiling of the aircraft.
So if there are issues with the UK access to F-35, no one else stands a chance!