John Ruiz was sitting at McCarran Airport in Las Vegas Tuesday afternoon waiting to launch a political campaign. It’s that time of year and, more to the point, boxing has become that kind of sport.

The two-time World Boxing Association heavyweight champion was headed to Buenos Aires, where he and his attorney, Tony Cardinale, will make their case with the WBA’s executive board that the alphabet organization should follow its rules and mandate that Ruiz and another former WBA title holder, Nikolay Valuev, fight immediately for the interim title. This might seem a given to some now that reigning champion Ruslan Chagaev’s ruptured Achilles tendon has sidelined him for at least the rest of the year, but in boxing seeing one of these organizations follow its rules is as rare as sighting a unified heavyweight champion.

The latter hasn’t existed since 1999. As for the former, don’t ask.

On Thursday, Ruiz will argue that Chagaev’s most recent injury means he will not have made a mandatory title defense for nearly two years by the time he’s again healthy enough to fight. Chagaev first won the WBA belt from Valuev on April 14, 2007 and under WBA rules had a year to defend it against the No. 1 contender. Chagaev was set to face Valuev on July 5 to fulfill that obligation but tore the Achilles tendon in his left ankle in his final day of sparring and is out indefinitely after surgery on Monday to repair the damage.

Just over eight months ago, Chagaev had to pull out of a scheduled unification fight with then WBO champion Sultan Ibragimov due to a bout with hepatitis B, which has further delayed fulfilling his mandatory defense. He was granted a non-mandatory title defense against Matt Skelton in January but now is facing possibly two years without having defended that title against the WBA’s No. 1 challenger. For Ruiz, that means it’s time to fight, although in his case the fight will in a meeting room, not a boxing ring.

“I think if I was a betting man I’d bet on them following their rules,’’ the 36-year-old former champion said. “We spoke with the Boston Celtics’ team physician and he said that with that kind of injury it’s 12 to 18 months before he’ll be fully healed.

“The WBA rules clearly state what has to be done. The top two contenders, which are Valuev and me, have to be allowed to fight for the interim title. Chagaev’s got to be stripped.’’

Ruiz is ranked No. 2 at the moment and is coming off a one-sided points victory in March over Jameel McCline in a WBC title eliminator. While he has lost three of his last five, they include a split decision to Chagaev and a disputed majority decision to Valuev that cost him the WBA title on Dec. 17, 2005. That loss has actually given Ruiz (43-7-1, 29 KO) reason to believe he can beat the 7-foot, 324-pound Valuev, primarily because both he and the majority of the crowd in Berlin that night believed he already had.

“I thought I won the first time,’’ Ruiz said of Valuev. “To me, it was one of the easiest fights I had in my career. I went 12 rounds and was not tired at all. I was surprised actually how easy it was because with a guy that big you basically have to keep going to the body.

“Never once did I feel threatened. Before they announced the decision I felt I’d won easy. Then it was announced and I was very disappointed.’’

So, too, was the crowd of around 10,000 at Max Schmeling Halle in Berlin. They lustily booed the decision (116-114, 116-113 and 114-114) even though Valuev is promoted by Germany’s Wilfried Sauerland and had been fighting primarily in Germany for the previous two years.

Since that fight, Ruiz has twice changed trainers and abandoned his long-time manager, Norman Stone, in a move that has resulted in a potentially messy lawsuit filed by Stone. Yet Ruiz believes he is in the best position he’s been in in years with veteran Manny Sciaca training him and a potential big opportunity – literally and figuratively – looming in front of him in the person of Valuev.

“My last fight with McCline people said I’d changed my style and was more active,’’ Ruiz said. “I didn’t really so much change my style as I changed my trainer. I’d only had a few months with Sciaca when I fought Chagaev and I still lost a close split decision in Germany.

“I’m glad I’ve moved on. Since Gabe LaMarca retired I didn’t really have a trainer. Stoney handled it but he wasn’t really a trainer. After Gabe left I wasn’t learning anything and I started to slide back. There were times people said I was having problems because of who I was with but I respected Stoney and let it go for a while until I realized I was sliding back, not going forward.

“I finally put my foot down and said we needed to get a trainer in here but Stoney was always criticizing whoever it was. With Manny it feels like a weight has been lifted off me. I was getting stale. Now I feel like I’m improving again.’’

That was apparent against McCline in a fight Ruiz won by a wide margin on all three judges’ cards. Now he is hoping to make a larger statement against Valuev but before he can get a shot at the WBA title for a third time he first has to win in an arena where too many decisions have been made in recent years – in a board room rather than a boxing ring.

“I hate to say it but I’m at the end of my career,’’ Ruiz admitted. “I got two good years left and I want to move forward. After I beat Valuev it wouldn’t make sense for me to move backward. I want to move forward and fight the other champions and make some noise.’’

When Ruiz was told that IBF and WBO title holder Wladimir Klitschko had said publicly many times that he will not feel he is the true champion until all the titles are unified, Ruiz reacted with some amazement.

“I’m very surprised to hear Klitschko said that because he doesn’t fight anybody,’’ Ruiz said. “For the heavyweight division to get back to where it was the best have to fight the best, like when Bowe and Holyfield and Foreman and Tyson were all around.

“When you become champion it’s like becoming the President. You worked so hard to get there you don’t want to lose it and the only way you can lose it is if you fight somebody, so they don’t. Too many guys rather hang on to the title by fighting Joe Schmoes than take a risk at being great.

“If we start fighting each other, you’ll see some movement. That would bring back the fans. You’ll see them interested in the heavyweights again, but only if we give them a reason to get interested.’’

John Ruiz hopes to do that first by winning his argument with the WBA. After that, it will be up to him to keep his word about what comes next.

“I want to make a mark,’’ said the first and only Latino to have won any form of the world heavyweight title. “I’m 36 but right now I’m more motivated than I was. This is like a rebirth for me.’’

If he gets his way and the other champions concur, it could finally be one for the long dormant heavyweight division as well.