What some call "stealthy" other would call "open deception" or "lies" -- like Democratic activists pretending to be Republicans in New Hampshire, or (as this article brags) funding ads on issues you don't care about to bring down a marriage leader like Marilyn Musgrave:

The Gill Action Fund’s new leader promises to continue the organization’s brand of stealthy, behind-the-scenes activism.

...According to a 2008 report in The Advocate, Gill Action in the 2006 election directed $2.8 million in nationwide contributions through its OutGiving program to 68 candidates across 11 states, and 56 of those candidates won. One of the more controversial ads funded by the organization was deployed against former Republican Rep. Marilyn Musgrave, author of the Federal Marriage Amendment. It depicted an actress dressed like her stealing a watch from a corpse in an open coffin, criticizing her for her vote on a tax for funeral homes. -- The Washington Blade