SACRAMENTO — Carly Fiorina has pulled slightly ahead of her Republican opponent in the U.S. Senate race, Tom Campbell, according to a poll by the Public Policy Institute of California.

Fiorina leads Campbell 24 percent to 23 percent, while a third candidate, Assemblyman Chuck DeVore, has the support of 8 percent of Republican primary voters. Fiorina had been behind Campbell by 11 points — 27 percent to 16 percent — in January.

"Republican primary voters very clearly are becoming more engaged," said Julie Soderlund, Fiorina's spokeswoman. "It's clear that they're learning about Campbell's support for tax increases and of Carly's strongly held views as a fiscal conservative."

Neither candidate has gone on air, so the numbers are very preliminary, said James Fisfis, Campbell's spokesman.

"It's sort of irrelevant at this point," Fisfis said. "We expect both candidates to launch ambitious advertising campaigns at some point. We're in an early part of the campaign. And the burden is a bit on Fiorina to start first because she has a longer sequence to work through. We have a more defined profile, so she has to raise her profile to the same level."

Meanwhile, Fiorina and Campbell are essentially even with U.S. Sen. Barbara Boxer in the poll. Campbell, a former congressman, holds a 1-point lead over Boxer, at 44 percent to 43 percent. Fiorina, the former CEO of Hewlett-Packard, was one point behind Boxer, at 43 percent to 44 percent.

Contact Steven Harmon at 916-441-2101.