An editorial cartoonist, also known as a political cartoonist, is a artist who draws cartoons that contain some level of political or social commentary.
The most common outlet for political cartoonists is the editorial page of the newspaper, although there have also been a few political cartoonists who have established a presence alongside "mainstream" comic strips. Doonesbury is the best example of this style of editorial cartoon.
There is Pulitzer Prize awarded every year for America's top editorial cartoonist — see Pulitzer Prize for Editorial Cartooning.
Famous American editorial cartoonists:
British editorial cartoonists