May be who is good speaker is sentence politician-
The politician made a speech.
I do not wish to be a politician. or We do not need more politicians
If I'm running for political office, am I a politician or a musician?
There are few blatherskites more deserving of a generous bescumbering as the politician.
No, it shouldn't be capitalized.
The politician was soo sad cause he did something wrong 
The abolition of slavery was a significant historical milestone in the fight for human rights.
Example 1: The politician supported the law of no homework.Example 2: The local politician was quite happy to be in pictures helping the community
She accidentally misquoted the author during her presentation, which led to confusion among the audience.
The politician vehemently denied the allegations against him.
The wording of your sentence must be clear.
A politician's trustworthiness is always in question.