washington u.s. asia experts serve past republican administrations say monday would back hillary clinton presidential race donald trump presidency would lead ruinous marginalization unite state region open letter eight former senior officials say global strategic competition grow include china absolutely wrong time elect unstable ill-prepared amateur vision foresight meet manifold challenge 21st century say republican nominee offer bluster preposterous panaceas asia would wreck country credibility economy leadership short order signatories letter include michael green serve president george w. bush top asia adviser white house jam clothe former deputy assistant secretary defense patrick cronin former senior official u.s. agency international development trump get chance put nostrums practice asian countries would force shift towards state challenge unite state notably china might seek security nuclear weapons former officials say short trump brand ... become america brand expect ruinous marginalization asia unwanted compliance rule chinese challengers set say letter late repudiation trump candidacy republican national security specialists last week 50 former republican national security officials include former cia director call trump unqualified lead say would reckless president american history trump respond statement deride signatories members fail washington elite deserve blame make world dangerous place trump cause alarm asia beyond say would consider let japan south korea build nuclear weapons rather rely unite state protection north korea china make u.s. ally anxious trump also irritate beijing comment compare u.s. trade deficit china rape one chinese state newspaper equate hitler time beijing also see trump businessmen could probably negotiate may also hope would less tough human right clinton republican asia experts say trump presidency would 'ruinous