The 2010 Massachussets U.S. Senate Special election, a contest between the little known Republican Scott Brown, and the Democratic Massachussetts Attorney General Martha Coakley saw Brown win in a state where Democrats outnumber Republicans 3-1.
Throughout most of the campaign, Coakley was seen as the favorite to win because of Massachussett's blue tilt—with Brown being seen as an underdog. However, Brown—tapping into the zeitgeist of dissatisfaction with government spending—was able to run a campaign that ended up winning Mass.
Here, he criticzised the Patient Protection and Affordable Care act negociations for potentially creating a public option, arguing that Massachussetts shouldn't pay for the healthcare of other states.
Beyond this he argued for lower Taxes and lower government spending; heavilly engaging on the stump throughout Massachussetts and outworked Coakley, helped by a large cadre of Tea Party volunteers who came to the state to help him.
Beyond this, Brown was helped by multiple major Coakley missteps, not being able to identify Popular Red Sox commentator Curt Shilling, refusing to and scoffing at brown for shaking hands outside of Fenway Park, whilst ceding the ground to Brown so that he could define himself.
Eventually running against 'the Democratic machine,' and evaporating Coakley's early lead—Brown won52-47%, winning thanks to strong margins in Central and Southern Massachussetts, while Coakley won in the Democratic bastions of Boston, Western Massachussets and Martha's vineyard