The most common and most likely answer to this crossword clue is the 8 letter word LIBERALS
I've seen this crossword clue in The Daily Telegraph
L
I
B
E
R
A
L
S
Buddy explains!

The straight part
We know that "politicians" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case politicians = liberals.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does LIBERALS mean?
LIBERALS noun- One with liberal views, supporting individual liberty (see Wikipedia's article on Liberalism).
- Someone left-wing; one with a left-wing ideology.
- A supporter of any of several liberal parties.
- One who favors individual voting rights, human and civil rights, and laissez-faire markets (also called "classical liberal"; compare libertarian).