“If you want a friend in Washington, get a dog.”

— President Harry S. Truman

And if you want Mark Sanford to endorse old friend Lindsey Graham’s re-election bid, get ready to wait.

Our junior senator, Tim Scott, has been repeatedly declining the opportunity to give our senior senator, Graham, his backing against four (so far) announced 2014 Republican primary challengers.

First, Scott ducked that chance several times Wednesday night on CNN’s “Crossfire.”

He pointed out that he’s also running for the Senate next year.

Scott stuck to that stance Friday when asked about it by my dogged colleague Schuyler Kropf after giving the keynote speech to the Palmetto Policy Forum’s Vision SC Summit at Charleston Place.

Sanford wasn’t in a Graham-boosting mood either Friday afternoon.

During a phone interview, Sanford mocked the benefits of getting “one political figure to endorse the other,” asking me: “Congress’s approval rating is what, 10 percent?”

Actually, it’s a record-low 9 percent in the latest Gallup poll.

As for endorsing Graham, Sanford said: “In fairness to him, I’d have to have a conversation with him first.”

In fairness to logic, why?

Though Graham didn’t quite endorse Scott, he did hail him as worthy Senate material nearly a year ago, a mere five days before Gov. Nikki Haley announced that she would appoint him to replace Jim DeMint.

As Graham told NewsMax back then: “I’m going to stand by Gov. Haley because it’s her constitutional prerogative and I trust her judgment. A guy like Tim Scott is just a great conservative that would be transformational, but you’ve got a lot of people to choose from.”

Graham even extended that “fine with anybody she chooses” umbrella to Sanford’s ex-wife: “I know Jenny well. She’s a very talented lady. Again, it’s the governor’s decision. And my job is to work with the new person.”

Picky, picky, picky

So Graham’s job is to work with Scott even though Scott shows no interest — yet — in helping him keep his job.

So some incumbents, including Graham, understand and hold no grudges when fellow party members fail to endorse them (see astute colleague Brian Hicks’ column coming in Sunday’s paper).

Graham does draw angry thunder from the tea party right for being soft on immigration and Obamacare. That’s because he responsibly backs immigration reform — and wisely opposed last month’s quixotic quest to “defund” the (un)Affordable Care Act, distracting the public from the law’s inherent folly.

Yet Graham has been too quick to advocate the use of U.S. military force and to defend the National Security Agency’s mass collection of Americans’ private communications.

Hey, nobody’s perfect.

Back to the ongoing ripple effects of DeMint’s quitting on us with four years left in his second Senate term to become the highly paid president of the Heritage Foundation:

Sanford (Mark, not Jenny) made a surprising political comeback this year, winning his old 1st Congressional District seat after Scott vacated it to fill the opening created by DeMint’s abrupt exit.

That extended this remarkable political achievement that eluded, among many others, Abraham Lincoln, Strom Thurmond, Fritz Hollings, Richard Nixon, Ronald Reagan, George H.W. Bush, Bill Clinton, George W. Bush and Barack Obama:

Sanford has won every political race he ever entered.

And as he reminded me Friday, he won this year with little or no help from the party: “I didn’t get any endorsements.”

Not so Bright

But Graham shouldn’t need any endorsements to win the 2014 primary. The heaviest hitter among his lightweight GOP opponents (again, so far) is state Sen. Lee Bright of Spartanburg.

Bright, however, is a loose cannon who in August accused Graham of serving as “a community organizer for the Muslim Brotherhood” during a trip to Egypt. Bright has also filed bills to make gold and silver coins legal tender in our state and to exempt firearms produced in South Carolina from federal regulation.

At least those far-fetched notions weren’t passed into law by our S.C. Legislature.

On Thursday, though, the U.S. Senate nuked the filibuster option that limits the majority party’s power to stampede the minority.

Sanford rightly decried that “nuclear option” obliteration of “a tradition of careful deliberation that’s been around for over 200 years.”

Scott — and Graham — agree.

See, Graham remains a solid conservative, with or without endorsements from his old friends.

And whether you’re in Washington, Charleston or anywhere else, if you want a friend who doesn’t care where you stand on immigration, follow that advice from the only man who ever exercised the real nuclear option:

Get a dog.

Frank Wooten is assistant editor of The Post and Courier. His email is wooten@postandcourier.com.