U.S. Sen. Lindsey Graham promised Tuesday to pursue the $400,000 needed for a study to deepen Charleston Harbor and said President Barack Obama's decision to exclude it from his 2012 budget could send port business elsewhere.

With the Panama Canal expansion moving toward its 2014 completion, shipping lines continue to deploy larger container carriers that demand deeper drafts in the ports they call. Charleston holds the distinction of being the deepest harbor along the South Atlantic, but it still cannot accommodate the mega-ships in every tide.

South Carolina needs an estimated $250 million to $300 million to take the shipping channel depth to 50 feet, from 45 feet, so it can capture business currently traveling through other places to reach markets closer to Charleston. But first it needs that $400,000 for a study to move the project along.

"If the Port of Charleston did not exist in the fashion to be competitive past 2014, what would it mean for our economy?" Graham asked during a conference call Tuesday. "It would mean devastation, I think."

The South Carolina Republican described two possible solutions to the dredging dilemma: to pass U.S. Sen. Jim DeMint's legislation that would change the funding process on port projects, specifically the way the Army Corps of Engineers spends money, or to direct funding from Congress to the Port of Charleston.

Although DeMint, also a South Carolina Republican, stands at the helm of the bill to reform port funding, he also diametrically opposes congressional earmarks. In a prepared statement, DeMint advocated a new law that would eliminate the Army Corps' more than 1,000 political earmarks.

"Congress must pass legislation to reform the Army Corps of Engineers that will eliminate their backlog of wasteful earmarks, let them focus on true priorities and allow states like South Carolina to keep the taxes collected at our ports to use in our own state," he said.

While Graham looks to either reform or an earmark as the most viable means for getting the cash, officials at the State Ports Authority instead hope that the Army Corps will be able to include the study in a "work plan" it could draw up this spring. Graham calls that option a temporary fix.

"What I'm looking for is not something to solve a political problem for 12 months, but a plan that will allow the port to be deepened," he said. He added a warning that if South Carolina has no strategy in place by April or May, it could lose business already calling on Charleston Harbor.

"If you're worried about creating jobs in America, then the last thing you'd want to do is shut down a port that's an economic engine for an entire region," Graham said.