Political statement isn't finished: that's obvious (8)
I believe the answer is:
Here is my best explanation:
'that's obvious' is the definition.
('manifest' can be similar in meaning to 'obvious')
I cannot understand how the remainder of the clue works.
(Other definitions for manifest that I've seen before include "Conspicuous; cargo list", "Plain - cargo list", "Clear, inventory", "(Of ghost) appear", "List of ship's cargo or passengers", "Clear, obvious", "It's obvious", "The ship's cargo list is obvious", "Easily noticed - cargo list" and "Customs document listing contents of ship or plane".)