Mitt Romney, who's been focused like a laser beam on taking down President Obama, switched gears Wednesday and went after Newt Gingrich ahead of South Carolina's Republican primary Saturday.
Romney started with job experience -- mocking Gingrich's claim that, as a congressman, he helped create millions of jobs.
"Congressmen taking responsibility or taking credit for helping create jobs," Romney quipped, "is like Al Gore taking credit for the Internet."Full CBSNews.com coverage: Election 2012
Romney's shift in focus shows just how concerned his campaign is about Gingrich's recent rise, which was fueled by his strong showing in Monday night's debate. A brand new poll from Politico.com shows Gingrich cutting into Romney's lead -- they're now just seven points apart, putting Gingrich in striking distance.
For his part, Gingrich said, "I fully expect the Romney campaign to be unendingly dirty and dishonest for the next four days because they are desperate -- they thought they could buy this."
Romney also is hitting Gingrich over leadership, with ads featuring some of his former colleagues in Congress. They paint Gingrich as a loose cannon.