Former GOP presidential candidate Rick Santorum is expected to arrive in the Lowcountry today to campaign for 1st Congressional District hopeful Curtis Bostic.

Bostic’s opponent, former Gov. Mark Sanford, announced Tuesday that he had picked up the endorsement from yet another former 1st District candidate.

Their maneuvering comes a week before their April 2 runoff race and on the same day that a new poll found both Republicans deadlocked in a contest with Democrat Elizabeth Colbert Busch.

Santorum, a former U.S. senator from Pennsylvania who campaigned for president extensively in South Carolina in recent years, said his Patriot Voices political action committee would back Bostic, and they are expected to campaign together today.

Sanford announced that Jonathan Hoffman, a former White House official under President George W. Bush, was the sixth former 1st District Republican candidate to throw his support to Sanford since the 16-way GOP primary last week.

Hoffman said his decision was based in part on Sanford’s “clear record in Congress and as governor of working to address this threat (of debt and deficits) with meaningful spending cuts and standing up to special interests.”

Only one of the 14 former candidates, former state Sen. John Kuhn, has endorsed Bostic.

A new Public Policy Polling survey found Sanford with a 53-40 lead over Bostic in their runoff, and the same poll found Bostic and Sanford essentially tied in a hypothetical runoff with Colbert Busch.

The poll gives fresh hope to Lowcountry Democrats that they can capture a seat that’s been in Republican hands since 1980.

The district, which stretches from Beaufort to Berkeley counties, is more Republican than South Carolina as a whole; it voted for Republican Mitt Romney last November by a 58-40 margin.

The winner of the April 2 GOP runoff will face Colbert Busch and Green Party candidate Eugene Platt in a May 7 special election.