WASHINGTON — There’s a libertarian pizza delivery man in North Carolina threatening to eat away enough votes to decide that state’s next senator. There’s a former Republican lawmaker, Larry Pressler, in South Dakota now running as an independent giving cowboy poetry readings. In Kansas, another independent — millionaire businessman Greg Orman — came out of nowhere to threaten a Republican who’s been in the Senate for almost two decades.

And then there’s the former green-energy entrepreneur whose 2003 road trip inspired a “Fantastic Four” comic and who keeps in his office a vial of ocean water he collected on a recent voyage to Antarctica. The difference between this guy and the other colorful outsider candidates? Sen. Angus King of Maine has been elected. And while this former governor has caucused with the Democrats since he was elected to Congress as an independent in 2012, he has left the door open to switching sides after the midterms.

“I don’t know,” he says. “The only, the only possibility would be if the Republicans are in the majority and they can offer me something that would be especially advantageous to Maine. Somebody said, ‘You may be a committee chair.’ I don’t think so. I don’t think anybody would want me that much.”

Depending on the outcome, if King’s choice would determine the balance — a big “if” but possible — of the Senate, he’d have a lot of bargaining power. These are the swings in influence that independents can have in the Senate. One day, King bragged about the humble task of getting photographs hung in a barren hallway of the Capitol and on another, he was playing a key role in last year’s student-loan legislation negotiations. But for now, the mustachioed man is doing pretty much everything in his power not to be another splashy story.

“For the purposes of your article, I don’t know how to say this without sounding boastful, but you can verify this,” King says, while walking through the Capitol basement last week on the way to his office from a hearing on Ebola, “one of my characteristics here is going to hearings and staying and listening.”

In 1994, when King ran as an independent for governor, he was the ultimate disrupter and outsider candidate. He had made millions working in the alternative-energy field but had never sought public office. A Boston Globe Magazine article from his election that year noted that he wrote a book on a laptop (one that he traveled with in his car) and used the Internet to answer voters’ questions. He was elected as the only governor in the country not affiliated with a party.

These days, the 70-year-old has reached the position of godfather to the independents. He’s also reached peak-Dad.

His office is decorated with the browns and burgundies and a couch that matches the remaining tan in his otherwise white mustache. The father of five keeps on an end table a book he published about the RV road trip he took with his family after he left the governor’s mansion. It’s got a punny title — “Governor’s Travels” — and doubles as a photo album of him standing next to signs that say either “Angus” or “King.” It’s also a tribute to the vacation beard he once had (“I got rid of it when I started to look more like Santa Claus than Willie Nelson,” he says).

King hasn’t been a presence on the 2014 campaign trail. In fact, he just got back from a nine-day trip to India, Pakistan, Qatar and Afghanistan with one of his best buddies in the Senate, Timothy M. Kaine, D-Va. But his name is ever-present.

“Both (Orman and Pressler) are using me as an example,” King says in his office. “It’s hard running as an independent. I wouldn’t have won the Senate election if I hadn’t been governor. I had credibility. The hard part is getting voters to the point where they think it’s thinkable and not a waste of time.”

It makes sense that this could be a banner year for independent candidates. Congress is the most partisan it’s been in years while also suffering from historically low approval ratings. Coincidence? For the fourth year in a row, a National Journal study found that no Senate Democrat was more conservative than a Senate Republican, and no Senate Republican more liberal than a Democrat. Not only is there no ideological overlap between the parties, it’s predicted to get worse.

This has led to a lot of pontificating about how broken the system is and how it will take someone from outside the party to fix it. Orman told The Washington Post that only an independent like him can “hold both sides equally accountable,” and Pressler offered the same type of platitudes: “I offer a practical, problem-solving, moderate approach to governance.”

King, having been elected on this message, says he understands the need for some new blood.

“There are a lot of people here who have never seen it work,” King says. “It’s like being on a football team that has lost every game for five years. Eventually, people just get used to losing.” Or they start fielding new players.

King says he has talked with Pressler and Orman on the phone to offer advice. He told them to “keep their powder dry about the caucusing question even though they are going to be asked a thousand times” and to just be themselves out there. After all, that’s the main benefit of being an independent.

During his Senate campaign, King says he began to worry about what it would mean if he decided to caucus with the Democrats. He called up former senator George J. Mitchell, the powerful Maine Democrat, to voice his concern.

“I said, ‘George, I’m worried if I caucus with the Democrats that I’m going to be compelled to vote certain ways and there will be a lot of party discipline,’ ” he says. “He laughed out loud and said, ‘Angus, we’re talking about Democrats here.’ “

King says that in his two years in the Senate, Majority Leader Harry Reid, D-Nev., has called him for a vote only once (for what King called “an obscure amendment on an agriculture bill”), a request he respectfully denied.

So, while King is happy to pick up the phone and tell Pressler and Orman “what a luxury” it is to be an independent, he isn’t about to hop on a plane to, say, Kansas to stump.

“I haven’t endorsed,” he says. “In part, because Orman is running against (sitting Republican Sen. Pat) Roberts, and my principle, which I decided before campaign season, is that I’m not going to campaign against one of my colleagues. … I think it’s one of the things that contributes to this place not working. How can you work with someone if you went into their state to campaign against them?”