Though she still needs to win the republication nomination on June 8, she's already challenging democratic senator Barbara Boxer.
"Meet me in Mendota. Come see what you have done. What you bureaucrats and extreme environmentalists have done to the people of the Central Valley," Carly Fiorina said.
An exclusive action news poll conducted this week by Survey USA shows Fiorina is the frontrunner for the republican nomination.
46 percent of voters surveyed supported Fiorina, while Tom Campbell is a distant second at 23 percent.
Chuck Devore is running third with 14 percent.
Just three weeks ago, Campbell was considered the front-runner with an eleven percentage point lead over Fiorina.