Republican voters in California have swung behind Mitt Romney, with the national presidential front-runner crushing his rivals by double digits and substantially expanding his support in the state, a new poll has found.

Romney won 42% of registered Republican voters, with his closest rival, Rick Santorum, trailing by 19 points, according to the USC Dornsife/Los Angeles Times poll. Newt Gingrich and Ron Paul were a distant third and fourth.

Romney’s support has risen by 15 points since a November USC/Times poll when Herman Cain was his closest competitor. (The former businessman has since dropped out.)

Yet there remains a palpable lack of enthusiasm for the Republican field. Half of GOP voters said they wished other candidates were running for president.

Barbara Foley, a 73-year-old Republican, said she would prefer former Florida Gov. Jeb Bush, Florida Sen. Marco Rubio or Rep. Paul D. Ryan of Wisconsin. She decided to vote for Romney by process of elimination — she says Santorum is too socially conservative, Gingrich is smart but a “loose cannon,” and Paul — “well, I just think he’s nuttier than a fruitcake.”