v. To convey information or cast another person's remarks or actions in a biased or slanted way so as to favorably influence public opinion.
1999
he Tories, led by David McLetchie, are charging their 18 MSPs pounds 3,500, giving them pounds 63,000 to spin the party line.
1998
Spin is the perspective that newsmakers and their minions put on a story to minimize any damage it might cause. As defined by political columnist and word maven William Safire in his New Political Dictionary, spin is "deliberate shading of news perception; attempted control of political reaction."
1977 (earliest)
What Pertschuk is accused of is being too ardent a consumer advocate, of "lobbying" members of the committee on behalf of things he thinks are good, of putting his own philosophical "spin" on options, of having excessive influence on Magnuson; in short of acting like the "101st senator."
This stalwart member of the political lexicon probably came from phrases such as "putting a positive (or negative) spin on" something. In turn, this notion of influencing direction almost certainly came from sports such as baseball and billiards where players impart spin on a ball to change its course.