Republican strategist Karl Rove told GOP presidential candidate Mitt Romney to "light a spark" Thursday in the debate, writing in an op-ed that most GOP voters "like him" but just need to get excited about him as the nominee.

Rove, President George W. Bush's former senior adviser, assessed the two frontrunners for the GOP nomination in an op-ed for the Wall Street Journal, but overall had more praise for former Massachusetts Gov. Romney than for his chief competition in the polls, Texas Gov. Rick Perry.

Rove wrote that Perry has performed "okay-to-mediocre" compared to Romney being "crisp, sharp, reassuring and in command during the debates."

"Much of [Perry's] support is based on what people believe him to be rather than what they know him to be," Rove wrote. His advice to Perry is to change his rhetoric on Social Security, where his position has been under attack from Romney.

Romney needs a "stronger explanation" for the healthcare law he implemented in his state while governor, Rove wrote. Romney's healthcare bill has been criticized as similar to President Obama's reform bill.

Rove also offered a boost to former Pennsylvania Sen. Rick Santorum's campaign by suggesting Santorum can compete with Rep. Michele Bachmann (R-Minn.) for the social conservative vote.

"The 2012 Republican sweepstakes is far from over," Rove wrote, noting that at this time during the 2008 campaign, the eventual GOP nominee Sen. John McCain (R-Ariz.) was trailing two frontrunners and Romney, who eventually became McCain's chief competition, was polling in the single digits.