A Public Policy Polling survey conducted on Friday and Saturday among likely South Carolina voters finds that Barack Obama and John McCain are widening their leads.

Barack Obama leads Hillary Rodham Clinton 44 to 31 percent, while South Carolina native John Edwards follows with 16 percent. Obama holds a slight edge among likely Democratic female voters, but his margin tightens to 42 percent to 37 percent over Clinton.

A strong showing by Clinton tomorrow in Michigan and Nevada later this week could slow down Obama’s momentum.

For the GOP, John McCain captured 28 percent of the surveyed Republicans to Huckabee’s 21 percent. Evangelical voters in South Carolina are expected to play a major role in the race, but the survey finds that only 16 percent of respondents cited moral and family values as their issue of greatest concern. Huckabee was the choice of 52 percent of these voters. Most polled selected the economy and jobs as the issue they considered to be the most important and they opted for McCain as their pick.

South Carolina’s GOP presidential primary is this Saturday, while the Democrats will vote the following Saturday.

The survey sampled 1072 likely Republican primary voters and 510 likely Democratic primary voters and margin of error of 2.9 percent and 4.3 percent respectively.