Looking for a verb that would be the opposite of smear, from a political/public relations point of view
Solution 1:
The term hype is often used to play up or enhance a reputation. According to Cambridge
to make something seem more exciting or important than it is
Three additional definitions from American Heritage say
Excessive publicity and the ensuing commotion: the hype surrounding the murder trial.
Exaggerated or extravagant claims made especially in advertising or promotional material: "It is pure hype, a gigantic PR job" (Saturday Review).
An advertising or promotional ploy: "Some restaurant owners in town are cooking up a $75,000 hype to promote New York as 'Restaurant City, U.S.A.'" (New York).
This is not unsmear but a concept of promoting.
Another aspect of countering a smear would be a rebuttal. Again Cambridge
a statement which says that something is not true; She issued a point-by-point rebuttal of the company's accusations.
Solution 2:
Most positive I can think of is polish. Smear implies covering with dirt, whitewash implies covering it up. But if there is no dirt in the first place, and there are genuine merits to be highlighted, it is time to polish them up. 'Their smear campaign has hurt us. It is time to polish up our reputation.'
Solution 3:
To "spin" is political jargon for attempting to frame news or events in a manner favorable to yourself or your group. As in, "Stories are coming out about our candidate having numerous extra-marital affairs. We've got to spin this as 'popular with women voters'?"
But this is broader than just "undo the negative impact of a smear". It's also routinely used to refer to making an ambiguous fact look good for your side, or turning something potentially positive about an opponent into a negative.
Solution 4:
Lionize is a wonderful word.
Oxford Dictionary of British English:
give a lot of public attention and approval to (someone); treat as a celebrity: modern sportsmen are lionized and feted.
Some uses of it together with politicians on Google:
Will Dem re-enacters recreate the Chappaquidick incident as they lionize Teddy?
Requiem for a Reprobate: Ethiopian Tyrant Should Not Be Lionized
Some other possibilities are panegyrize, commend, laud.
Solution 5:
The opposite of a smear in P.R. is what is known as a puff piece or puffery:
Puff piece or fluff piece is an idiom for ... an article or story of exaggerating praise that often ignores or downplays opposing viewpoints or evidence to the contrary.