
Tories Parliament "the party manifesto": 166 hitsNo dictionaries I checked mentioned this difference in usage between the U.S. and U.K., though an attentive dictionary reader might infer it from the slightly different definitions that appear in the British and American editions of the Longman learners' dictionary:
Tories Parliament "the party platform": 123 hits
Democrats Senate "the party manifesto": 39 hits
Democrats Senate "the party platform": 1,800 hits
Longman Dictionary of Contemporary English (British English):
manifesto a written statement by an organized group, especially a political party, saying what they believe in and what they intend to do
Longman Advanced American Dictionary (American English)
manifesto a written statement by a group, especially a political group, saying what they believe in and what they intend to do: the Communist manifesto
(October 25, 2003)