LAS VEGAS, Nev. -- By Frank Curreri FOX5 News

Back when former President Bill Clinton’s libido got him into trouble, the smooth-talking southerner forced the nation to ponder what constitutes sex – and what does not.

And as Tito Ortiz and Chuck Liddell brace for Saturday night’s much-anticipated rematch, the outcome of the fight probably hinges on a Clintonian type of distinction: The difference between “thinking” and “knowing.” As the fisticuffs between former friends inches closer, what is going on inside of Ortiz’s head? Is he like The Little Engine That Could, “thinking” he can win? Or is he, like boxer Antonio Tarver before his historic upset over a once-invincible Roy Jones, ruled by a state of mind where he “knows” he will win?

I’m not a psychologist, but I play one in this column. Time for some gratuitous chest-pounding: I predicted Tarver’s victory over then-pound-for-pound king Jones – a pick nearly all of my reporter colleagues dismissed as crazy talk until it came to fruition and left ringside observers with mouths agape.

I vividly recall seeing Lebron James standing in the front-row, all blinged out in a white sweat suit and sporting jewelry that we can safely presume were diamonds, unless $150 million athletes have turned to cubic zirconia for their fashion needs. This scene will forever be etched in my mind of that night: Jones The Great sprawled out on the canvass unconscious, and Lebron shaking his head in disbelief and saying repeatedly into a cell phone: “I don’t believe the sh—that I’m seeing.”

Let me tell you, if Ortiz manages to upset Liddell, I too could wind up on my cell phone telling someone, “I don’t believe the “sh—that I’m seeing!” – provided Lebron doesn’t have the phrase trademarked, since pro athlete sorts like to copyright the most mundane, oft-used phrases these days.

Now if only Ortiz can get in Liddell’s face before the fight and ask him sarcastically, “Got any excuses tonight, Chuckster?” Hey, it worked for Tarver.

Though a 2 to 1 underdog, the Ortiz bandwagon seems to grow by the hour, with people reminding me of how talented and pissed off he is. On paper, I can see where they’re coming from. Ortiz is the stronger of the two, a superior grappler, a solid striker and boasts exceptional cardio. Liddell has a Kangaroo pouch for a stomach, the worst haircut in all of sport, and questionable stamina if pushed hard past the second round.

Liddell is a hard hitter and has awesome ground defense, but what about his age? He’s 37 after all, making him an anomaly in a sport dominated by twentysomethings and champs about 30 or so. What if Liddell, with a 19 and 3 record, gets old overnight?

Ortiz, meanwhile, is only 31 and riding a five-match win streak, which is supposed to boost his confidence coming into second go-round with Liddell (Buyer Beware: Two of those wins were over an aging Ken Shamrock, who lost 7 of his last 9 fights before retiring). The self-proclaimed Huntington Beach Bad Boy has said repeatedly he does not fear Liddell, a former training partner whom he dodged several years ago, though The Iceman begs to differ.

Make no mistake, Liddell’s public comments are serious fighting words. Growing up in blue-collar Baltimore, long before anyone had dreamed up the genius idea of an Ultimate Fighting Championship, I learned all too well that even seeming pacifists have a boiling point at which they will behave like raging pugilists.

Among enemies, there are well-established limits about what should – and should not -- be said. At the top of the “Never Say This To Your Enemy” list is this taboo: Any derogatory comment about the other guy’s Mama. The other big No-No is calling the other guy a coward, which is essentially what Liddell did.

On occasion, that kind of trash-talking can transform puny David’s into ferocious Goliaths. But will the insult embolden and rile Ortiz, who was knocked out in his first fight with Liddell?

What is certain is that, as usual, Ortiz’s long and spirited walk toward the Octagon is worth the price of admission, regardless of how the fight plays out.

No fighter milks drama better than Ortiz on his way to the ring. He doesn’t walk; he marches. Hero to some and villain to others, he favors an intense and fiery look rather than the stoic stare so many fighters wear.

Ortiz carries with him a two-sided flag which represents his own heritage: one-half American, one-half Mexican. Loud music will pump and the crowd will go wild. Rest assured, all of New Year’s Eve on the Strip will prove a distant second to the hair-raising electricity of that moment.

It would be memorable if Ortiz stole a page from Tarver on Saturday. In fact, on paper Ortiz matches up much better against Liddell than Tarver did with Jones. Tarver was much slower and less spectacular than Jones, and had not fought any big names. But he had in his favor that which is difficult to measure: He had obsessed about Jones for years after losing to him as a teenager. He knew Roy Jones’ tendencies inside and out and, most importantly, stepped into the ring knowing he would win.

When I interviewed Ortiz last month, I did not sense that same obsession, that same fire for revenge, that same conviction in himself. I perceived a gifted fighter who is still trying to win a battle in his own mind, perhaps still telling himself “I think I can, I think I can, I think I can.”

The odds are heavily stacked against someone with a “Little Engine” mentality toppling a great champion in his prime – and that is precisely what Liddell, winner by six straight knockouts, is at the moment. Despite his age, Liddell does not have a lot of wear on his body because he hasn’t had many wars and only 22 fights.

Still, in mixed martial arts, anything can happen in the blink of an eye, which is why we will all be watching. If Ortiz can somehow produce a fast-paced fight and take the match into the third round, he may manage an upset and prove a lot of us to be liars. Otherwise, if he loses again, he can see the situation as win-win: He will have pocketed a nice payday and probably never have to fight Liddell again.

Frank Curreri can be reached at: fcurreri@kvvu.com