Liberal America curtailed president's five year term (7)
I believe the answer is:
lustrum
'year term' is the definition.
'lustrum' can be an answer for 'term' (thesaurus). I am not sure about the 'year' bit.
'liberal america curtailed president's five' is the wordplay.
'liberal' becomes 'l' (abbreviation).
'america' becomes 'US' (United States).
'curtailed' means to remove the last letter.
'president's five' becomes 'strum' (I can't explain this - if you can you should give a lot more credence to this answer).
'us' with its final letter taken off is 'u'.
'l'+'u'+'strum'='LUSTRUM'
Can you help me to learn more?
(Other definitions for lustrum that I've seen before include "several years" , "Period of 20 ac years" , "Period of five years" , "Five-year period" .)