U.S. Sen. Lindsey Graham calls President Barack Obama by his first name and curses like a sailor in private conversations with Vice President Joe Biden, according to a new book on the Obama presidency.

The book — written by Washington Post associate editor Bob Woodward, who won a Pulitzer Prize for his coverage of the Watergate scandal — shows Republican Graham as willing to work with Democratic leaders.

That portrayal of Graham — as a moderate Republican who embraces bipartisanship — could spell trouble for the Seneca Republican in a 2014 GOP primary, where Tea Party Republicans, turned off by candidates who compromise, could threaten Graham’s re-nomination.

No one is speculating Graham will be defeated in 2014. But he could face a primary challenge from a candidate further to the political right. Already, one libertarian-leaning, Ron Paul-supporting state senator, Republican Tom Davis of Beaufort, is calling for Graham’s ouster in the GOP primary.

But, as 2014 draws nearer, Graham is moving to the political right, striking a contrast to the Graham of a few years ago, according to some political scientists, and the Graham of 2009, who was invited to the White House for a chat with newly elected President Obama, according to Woodward’s new book.

“People are going to listen to you unlike any other setting in any other time in your life,” Graham advised Obama. “Don’t ever let that be lost upon you.”

Today, however, that Graham has faded, said Dave Woodard, a Clemson University political scientist who ran Graham’s U.S. House campaigns in 1994 and 1996.

“He’s a different Lindsey Graham today compared to a few years ago,” said Woodard. “He is much more skeptical of Obama’s programs today.”

‘Wake-up call for Lindsey’

A few years ago, Graham was racking up plenty of foes in conservative and Tea Party circles:

• In 2010, Graham predicted the demise of the Tea Party, telling a New York Times reporter, “It’s just unsustainable because they can never come up with a coherent vision for governing the country. It will die out.”

• That same year, Graham’s bipartisan plan to grant citizenship to illegal immigrants who paid fines and back taxes and did community service, earned him the nickname of “Graham-nesty” among his critics.

• A cap-and-trade initiative that Graham pushed also would have required companies to buy and sell greenhouse gas emission credits. The proposal ultimately was abandoned but two county chapters of the S.C. Republican Party still censured Graham.

Today is a new day, and Graham knows it.

The Tea Party has proved it has staying power, particularly in S.C. GOP primaries.

S.C. Republican voters also have moved further to the right, enraged by Democratic policies that, they say, have saddled the country with debt and failed to revive the stalled economy.

Perhaps most important, recent S.C. political history has shown incumbency does not always translate to re-election in this polarized political climate.

Case in point: Bob Inglis.

In 2010, Graham hosted one of the first fundraisers for U.S. Rep. Bob Inglis’ re-election bid. Despite being well funded, the 4th District Republican incumbent from Greenville was pounded 71-29 percent in a GOP primary runoff, losing to now-U.S. Rep. Trey Gowdy of Spartanburg, who had Tea Party backing.

“Up until Bob Inglis, I think many people thought incumbents usually win,” Woodard said. “But (Inglis) just got killed. It could have been a wake-up call for Lindsey that you may not just lose, but you can get blown out of here.”

‘Necessary’ relationship

Graham’s office said Monday there is little new in Woodward’s book.

Graham has long been public about his relationship with the Obama Administration “as necessary.” For example, Graham recently went to the White House to discuss deepening Charleston Harbor, winning approval to make the project a priority.

Graham also is a long-time friend of Vice President Joe Biden, who, in the book, calls Graham in 2011 to find out why Republicans were pushing a tactic that Biden thought made no sense.

Graham agreed, using a half-dozen obscenities, according to the book.

Graham spokesman Kevin Bishop pointed Monday to Biden’s role in securing “the necessary authorization to move forward with the Charleston Harbor deepening project” as just one example of why it is good for South Carolina that Graham is in touch with the Delaware Democrat.

(Graham’s cursing, his office added, was part of a private conversation, not meant for public ears.)

But Graham’s office put the brakes on paying any additional compliments to the administration. “We are 50 days away from a presidential election and Senator Graham is committed to making Barack Obama a one-term president,” Bishop said.

These days, Graham is often an Obama critic, saying the president is failing to lead during the current Middle East unrest, detonating “debt bombs” that will explode the nation’s deficit and labeling as a failure Obama’s economic stimulus program.

Those criticisms do not represent Graham moving to the right, some allies insist.

“He sees just about every issue through a national defense/security prism,” said Shell Suber, a Columbia-based political consultant who was political director for Graham’s 2008 re-election bid. “If there is a lot of public discussion about something that has a security aspect to it, it may seem as if he is ‘moving to the right’ but usually he has always been there.”