Romney rivals looking for momentum
Mitt Romney's Republican rivals are struggling in South Carolina for a theme, momentum and most crucially, one strong challenger to consolidate conservatives' misgivings about the front-runner.
They have a week to halt Mitt Romney from sweeping to a third straight party primary victory in the race to decide which Republican will face Barack Obama in November.
But the dynamics that lifted the former Massachusetts governor to wins in Iowa and New Hampshire seem to be working for him in South Carolina.
South Carolina is often described as too evangelical and culturally southern for his background, but the former Massachusetts governor has benefited from a fractured opposition that has divided the anti-Romney vote for months.
Mr Romney has also benefited from shrewd and well-organised supporters. He uses TV ads to shore up his weaknesses and to batter the rivals he sees as most threatening.
Still, the state is known for campaign surprises, and there is still time for twists and turns. Undercurrents of anti-Romney sentiment, perhaps fuelled by his Mormonism, could be stronger than they seem.
In Iowa, the target was former speaker of the House of Representatives Newt Gingrich, who plummeted under the barrage.
In South Carolina, it is former Senator Rick Santorum, a long-time champion of home-schooling, anti-abortion efforts and other social conservative causes.
Mr Santorum nearly won the Iowa caucus, and some consider him the best bet for unifying the anti-Romney vote. But a private group that supports Mr Romney is pounding Mr Santorum in South Carolina with TV ads and mailings. So is Representative Ron Paul, the libertarian-leaning candidate who helped attack Mr Gingrich in Iowa.
Mr Paul's ads are especially harsh. They vilify Mr Santorum for pushing pet projects as a Pennsylvania senator, and they portray him as an insincere conservative.