B EFORE giving Gary Payton full credit for Paul Westphal’s firing, Vin Baker’s leading role in the killing of his Sonic coach deserves to be duly acknowledged.

According to a Seattle source, Payton, indeed, is everything I make him out to be, but upholds one redeeming notability … he doesn’t concede to a pedigreed soul at his position across the stat sheet.

Baker, on the other hand, “is a shell of a player, totally selfish and has no heart,” the source deftly decapitates. “Anybody who has ever been around him will tell you the same thing.”

Payton’s personality is a problem, but at least he comes to play and practice … most of the time.

Westphal’s biggest problem, as it turns out, was being unable to get Baker to play. To get him to stop playing like a washed-up All-Star/Olympian and begin impersonating a starter for a playoff team. To persuade him to perform occasionally with pride and passion.

Now Baker is Nate McMillan’s basket case.

Who knows? Maybe a different voice will make a difference. Maybe Sonic owner Barry Ackerley and President Wally Walker were correct to make a change before the 6-9 team got submerged any deeper under .500.

Maybe Westphal needed to go and the time was right to promote McMillan. Maybe he’ll have some fresh ideas on how to get through to Baker, how to make him less slow downstairs and upstairs, how to induce him to labor and compete.

“As much as everyone likes Nate, nothing is expected to change all that much,” the source maintains. “Nate knows the reality of the situation.”

What exactly is that reality, you ask? Ackerley and Walker have been at the mercy of Baker since the day they dishonored every conscientious NBA player by re-signing the same mutt who showed up in Seattle following the lockout terribly out of condition and emotionally destitute.

Despite Baker’s pronounced lack of fitness, professionalism and production, management grossly miscalculated, rewarding him with a seven-year, $86 million guaranteed deal before last season.

Meaning, Westphal was forced to ignore Baker’s uninterrupted disrespect for team goals, gameplans, play-calling and the coaching staff, specifically himself.

Meaning, Westphal was forced to endure an endless stream of lame excuses and glaring abuses.

Meaning, Westphal had no other choice but to give Baker an inexhaustible amount of chances.

After all, Baker has six years and $77M left on his obscene contract. As for Westphal, he was refused so much as a one-year extension past this season.

As usual, the inmates had taken control of the asylum. Payton did and said as he pleased without fear of retribution. But, again, at least, he was pleasantly prolific when he wasn’t playing the part of a punk.

Baker, meanwhile, was simply impotent, except when he was being mutinous. Which is why the Sonics went into overtime and overdrive in an effort to trade him to the Knicks for Patrick Ewing, as part of a four-team trade last summer. When it broke down, nobody worked harder or more creatively to reconstruct the deal than Walker.

“If we could’ve gotten Ewing and kept Horace Grant,” says a younger Sonic, “we could’ve competed with anyone – Lakers, Spurs, Blazers, anyone.”

At the same time, most New Yorkers were under the misconception the Knicks had almost achieved a coup in obtaining Glen Rice and Baker.

“I hope this doesn’t sound insensitive,” says someone close to Baker, “but had Vin gone to New York, he would’ve wound up in a psychiatric ward. He could not have withstood the city’s pressure from its fans and media. He could not have survived. It would’ve been child abuse.”

It hasn’t been much better in Seattle. There was serious talk last season that Baker suffered a nervous breakdown. Though he denied he was cracking under the strain of his mega-contract, continued excess weight and horror show at the free throw line, those around him told a different story.

“You can’t imagine what a wreck he is as a competitor and a person,” says one insider. “It’s sad.”

Sadder still, because Baker tries to hide behind his incompetence, insecurity and embarrassment. As a defense mechanism, he bad-mouths Westphal, the refs, opponents, whomever he can target for getting torched.

For example, it was Baker who ignited the atmosphere in Orlando (Nov. 6) when Westphal offered to resign. With about six minutes to go, the Sonics trailed by six. Despite Baker’s playing horribly and in foul trouble, Westphal diagrammed a play for him during a timeout. What he got in return was a vacant stare.

“Focus, Vin, focus!” Westphal scolded.

Baker responded by cursing out his coach.

The result: The Sonics completely blanked out, quickly falling behind by 15. Again, Baker responded, only this time at the refs. Westphal removed him before he could get heaved.

In the locker room, Baker sounded off. He ranted and raved about being mistreated by Westphal. Screamed it was the coach’s fault the team had lost and the coach’s fault the team was 1-4. Everybody standing outside could hear his spew, it was that loud, that vicious.

Guess who came to his rescue? Payton. He told Baker to shut up. Told him to grow up. Told him he was the problem. That’s when Westphal came out of his office and told them, “If you can’t play for me, I’ll quit.”

Don’t get this wrong, underlines one of the above sources. “Gary is Vin’s friend. He’ll stand up for him, which he’s done many times, because he knows the team needs him to be a force in order to be successful. But Gary’s also exasperated. He doesn’t know how to motivate Vin, either. Vin is driving Gary crazy, too.”

Saturday night’s massacre in Sacramento was jam-packed with its normal measure of madness. Aside from the Sonics being busted, 125-121, Baker was shamed by Chris Webber, 24-12 on the scoreboard and 12-5 on the backboard. In a matchup of alleged macho forwards, one came out looking soft as liquid soap.

The Sonics had dropped behind by 14 after one quarter, closed the gap to one point after two with Baker on the bench, then fell behind by 12 after three with him back in the lineup. Naturally, he responded in character.

First, Baker attempted to get ejected by woofing at the refs. Payton ruined that plan by escorting him away from his target. Next, he sold wolf tickets to Webber and actually made it seem as if he wanted a piece of him. The refs were compelled to toss both.

At Sunday’s practice, it was Westphal’s turn to toss Baker. He kicked him out of practice for not playing defense, and for a defective attitude. He then informed the juvenile delinquent he wouldn’t be starting again for the remainder of the season. Baker responded by going nuts on the coach.

Ackerley and Walker responded by firing Westphal.

And the Sonics have a new slogan to go along with their new coach: “McMillan And Strife.”