The former Speaker of the House of Representatives visited the San Diego Zoo and attended a fundraiser in Fairbanks Ranch. He later went to California's Central Valley.

In Fairbanks Ranch, Gingrich stressed one theme.

"Would you rather have $2 a gallon gasoline or $4 a gallon gasoline?" he asked.

Martha Kaloogian, who attended Gingrich's event, called him "authoritative [and] presidential."

Mike Pierce agreed, saying, "[Gingrich's] message is consistent and it's clear."

Gingrich's wife, Callista, joined him for the California campaign swing and spoke to a Republican women's group.

"Our only opponent is Barack Obama and we are committed to removing him from the White House," she said.

Gingrich put it this way: "Just beating Obama's not enough. We've got to change the laws [and] change the bureaucracies."

Gingrich said he is already looking beyond the Super Tuesday primaries in other key states in March. He said he wants to focus on winning California delegates in June.

A new national poll by CNN found Gingrich, whose win in South Carolina a couple weeks ago propelled him into the top tier of candidates, now in fourth place with 15 percent support.

Former Pennsylvania Sen. Rick Santorum led ex-Massachusetts Gov. Mitt Romney, 34 percent to 32 percent, which is within the margin of error. Ron Paul has 16 percent.

"This has been like riding Space Mountain at Disneyland," Gingrich told 10News in reference to the "ups and downs" of the GOP race.

Santorum, who released a television advertisement in the next big primary state, Michigan, calling himself a "full-spectrum conservative," emerged last week with wins in caucuses in Colorado and Minnesota, and a victory in a primary in Missouri.

Romney, a part-time La Jolla resident, was born in Michigan, and his father was governor of the state.

The CNN poll was of 1,026 people questioned between Friday and Monday.