WASHINGTON -- It's now virtually certain that Barack Obama will be the Democratic presidential nominee and Hillary Clinton will return to her day job in the Senate, wondering what she could have done differently in her ill-fated campaign for the White House.

Strategies, tactics and issues aside, Hillary would be the presumptive nominee today if her party's primary rules had included a winner-take-all system as the Republicans do, instead of the "no one left behind" delegate allocation system that says the loser should not go home empty-handed.

Under the Democrats' proportional system, delegates are awarded among the candidates in direct proportion to the vote each receives in the congressional districts, with some portion based on their share of the statewide vote. In the winner-take-all system used by the Republican Party, the candidate who takes a state primary, even by a single vote, wins all its delegates. But liberal Democrats are repulsed by what they consider to be an undemocratic, survival-of-the-fittest system that quickly eliminates the weaker candidates.

Number-crunchers who've analyzed the 45 or so primaries and caucuses held thus far figure that Hillary would have a 400-delegate lead today under winner-take-all. Instead, she stands 332 delegates short of the nomination-clinching 2,025; Obama needs 180 to grab the prize.

In the end, the proportional system worked against her strength in the big, delegate-rich states, which she consistently carried, and worked for Obama, who racked up his larger total by winning in many of the smaller states. Looking back, her list of big-state victories is impressive: California, Massachusetts, New Jersey, New York, Ohio, Pennsylvania and Texas. In a winner-take-all system, they would have pushed her well ahead of her rival, but for the proportional rule that gave him his share of the vote.

This is not to say that Obama did not win in some sizeable states, too. His list off 28 victories includes his home state of Illinois, Minnesota, Missouri, Virginia, Wisconsin, Washington State, Colorado, Connecticut, the Carolinas and Georgia. So while the news media focused on big state battles, he patiently and quietly kept winning in a lot small states, too, from Hawaii to Delaware, racking up his delegate numbers, and by impressive percentages, too. A survey of Obama's state-by-state vote totals shows him winning at least 16 primaries by between 60 percent and 80 percent margins, and boosting his delegate count proportionately. Outside of Arkansas, which she won by 70 percent, Hillary never broke into the 60s anywhere else.

Throughout the year's primary battles, I always made it a habit of asking Clinton supporters whether they believed it would have been far better for their party if it had switched to winner-take-all. The answer was usually the same: no. The proportional system was "fairer," it rewarded front-runners and second-tier candidates, giving them a chance to build support as they became better known to their party, they told me.

Now, I find more and more Democrats -- especially Hillary's supporters -- regretting the present system, which produced an interminable nominating process that has proved to be costly, divisive and politically exhausting. The Democrats come off as the party who can't get its act together, struggling to produce a nominee, while Republicans have picked their strongest candidate early and are confidently gearing up for their convention and the general election to come.

Former White House chief of staff Leon Panetta, who is supporting Senator Clinton, is among those who say he has changed his mind. The GOP's winner-take-all system is far more efficient, fairer and better for the party over the long term, he told me.

Last week, I asked the same question of veteran Democratic strategist Maria Cardona, who is also backing Hillary. After saying she wasn't sure at first, she replied, "Yes, I would go to winner-take-all," recognizing that it would have given her candidate a prohibitive lead at this point in the party primary schedule.

My guess is that this is only the beginning of a party-wide debate over the proportional system, which still has its diehard supporters. But for the time being, it appears that the losers want to switch to winner-take-all and the winners think the present system is as good as it gets.