Latest: Election results
Decision 2012: Complete election coverage
In early returns Tuesday night, Cantwell led Baumgartner 60 percent to 40 percent.
Cantwell, Washington state's junior senator, led from the start, amassing a war chest worth more than $8 million that dwarfed Baumgartner's effort, which added up to about $1 million.
Baumgartner is a first-term state senator from the Spokane area who previously worked as a foreign policy consultant.