The credibility of "American Idol" will be determined tonight.

And not because practically everyone has been forecasting that Diana DeGarmo will emerge victorious over Fantasia Barrino, even though Barrino is enormously talented while DeGarmo is not.

Last night, for example, Barrino brought the audience to tears, judge Paula Abdul called it "her night" and judge Simon Cowell called her final song "her acceptance speech," claiming she's the most talented singer to ever appear on any of the U.S. or international editions of "Idol." DeGarmo, meanwhile, turned in another of her signature karaoke-singer-turned-teen-pageant-veteran-turned-"America's Most Talented Kid"-finalist performances, causing judge Randy Jackson to note that she was "singing her face off."

No, it does not matter who wins. Just ask Clay Aiken, who lost to Ruben Studdard in the second edition of "American Idol" but has sold 2.5 million albums to Studdard's 1.7 million, according to the most recent stats from Nielsen SoundScan.

The show's voting system, however, is in a state of crisis, angering numerous viewer-voters and possibly explaining why, though "Idol" is the most watched program of the TV season, audience levels showed signs of slippage among 18- to 49-year-olds as the season progressed.

Even so, the Fox network and the show's producers steadfastly refused to acknowledge they have a problem, until recently.

Last year, Fox reported during the "Idol" finale that 24 million votes had been cast on the final Tuesday night of the competition, 134,000 more for Studdard than for Aiken.

But Verizon reported its call volume was up by 116 million calls that night, which a spokeswoman attributed to "Idol" voting, trade publication Broadcasting & Cable reported. SBC Communications reported its call volume on the night was up by 115 million.

That would seem to indicate that millions more votes were attempted than the 24 million that were recorded during the three hours the network left the phone lines open.

The next day, television critics were swamped with calls from angry viewers who had been unable to get through at any time during the three hours. The TV Column also heard from many people with the same story.

In response Fox issued a statement that set the tone for how it has handled all questions about the voting this season. The network said "there were no issues with the AT&T national phone system" and that it had anticipated "some" local exchange companies might be "challenged" by the call traffic and may have "reached their own local maximum capacity." This is why, Fox said, it kept the lines open for that additional hour.

In other words -- not our problem.

"Idol" is the most important show Fox has on its schedule; during the May ratings sweeps, it was practically the only thing Fox had on its schedule. It turned over nearly a quarter of its schedule to "Idol" broadcasts and tossed-together "Idol" specials like "Idol: The Final Three."

Thanks to "Idol," Fox will finish this TV season in second place among the 18-to-49-year-olds whom advertisers pay a premium to reach. At the end of the November sweeps, before "Idol" returned to its lineup, Fox was in fourth place in that demographic.

"Idol" is so important to Fox, the network plans to wait until the reality series returns in January to launch the largest chunk of its new series next season. At Fox, January is the new September, thanks entirely to "American Idol."

And yet, the network allows questions about the voting system to continue to plague this important franchise. This season the news media have written about it extensively while Fox continued to "smile its Cheshire cat grin," as the Associated Press put it in one of its numerous stories on the subject.

Especially startling was the week in which the most talented contestants, the Three Divas as they were called by Cowell, were the bottom vote-getters. Guest judge Elton John was not the only one to suggest that the voting was racist because all three of the women were African American; one caller to "The Tom Joyner Morning Show" angrily reported she had tried numerous times to vote for the three -- La Toya London, Jennifer Hudson and Barrino -- but all three lines were busy the whole time. Another caller speculated that the reason they'd received the fewest votes was that African Americans "don't text-message," while "little white kids" vote repeatedly with their cell phones.

(Viewers can vote by telephone or by text-messaging. Text-messaging is digital; phone lines are analog. Votes by text-messaging can stack up and be recorded later; phone lines become clogged and would-be voters get a busy signal. Text-messaging costs 10 cents a vote; phone voting is free.)

More recently, some viewers cried foul when London got axed while Jasmine Trias, who'd been uniformly trashed by the judges for her subpar performance that week, got voted through.

The viewers noted that, on the mainland, they have to compete for phone lines with millions of others in their time zone, while Hawaii, Trias's home state, with a population of just 1.2 million, is in its own time zone. That means Trias's many Hawaiian fans enjoyed a far less crowded calling period. Indeed, of the 29 states in Verizon's local territory, Hawaii logged more calls that night than anyplace else except the very populous states of New York and California, the AP reported.

Fox again went into full not-our-problem mode: "The producers and network have gone to great lengths to ensure the integrity of the voting process on 'American Idol,' " the network said in a statement.

"America votes, an independent company calculates the tally and the show reports those results."

Fox then tried to place the blame squarely on the viewers.

Host Ryan Seacrest opened the next Tuesday's broadcast by telling viewers, "Last week there was outrage when your votes [emphasis his] decided that La Toya London would not be" in the final competition.

The studio audience booed; Seacrest went back to his script:

"That's what you wanted! That's what you said! Or, maybe you just thought, 'Aw, she'll be fine,' and did not bother calling in. Well, you've seen what can happen."

Have we mentioned yet that AT&T is one of the show's biggest sponsors?

Seacrest continued: "Millions of people will be trying to get through at the end of the show. So the lines are bound to be busy. But do not give up. You will have at least two full hours to vote and you can vote as many times as you like."

Unbeknown to Fox or Seacrest, the Associated Press had assigned reporters nationwide to try to vote at the conclusion of that May 18 broadcast.

Last Thursday, the AP reported the results of its close encounter with the phone voting system that has "bedeviled the show and fueled conspiracy theories when talented competitors were axed over weaker ones."

AP reporters began trying to phone in their votes "as the last strains of the 'Idol' theme song faded," the wire service reported.

"Too late: the line's busy, chump. Try again. And again, and again . . ."

Out of more than 100 calls placed by the AP from Los Angeles and the home states of Barrino (North Carolina), DeGarmo (Georgia) and Trias (Hawaii), only four got through.

In Georgia, the AP said, the second call placed went through but after the caller hung up, the land-line phone went dead for 17 minutes. As soon as the tone returned, the reporter called the "Idol" line, got a busy signal and again the line went dead, for four minutes.

The next day, the network announced that the two finalists, Barrino and DeGarmo, each would be assigned three separate phone numbers. (Fox had already announced it would extend the voting period after last night's final performance broadcast, as it had done last year, only this time by two hours instead of one.)

"We had already planned on expanding the voting window for the finale, just as we did last year," executive producer Cecile Frot-Coutaz of Fremantle Media said in a statement. "With the volume of calls this season already exceeding last year's finale, we also felt it was important to give fans additional phone numbers in an attempt to reduce the congestion at local exchanges."

Gee whiz, if four-hour voting windows and more phone lines are an option, why not do that throughout the show's run, rather than putting the credibility of this franchise through the wringer week after week?

And, while we're asking questions, can anyone explain Paul Anka doing "My Way" with what's left of his voice at the end of last night's broadcast?

Fantasia Barrino, left, and Diana DeGarmo each got three songs last night to convince America she should win "American Idol." The result will be announced tonight.