If elections were all about heart and determination, both Hillary Clinton and Barack Obama could win the Democratic nomination for president.

Both have waged an epic Democratic primary battle that has energized the American political scene like few other electoral campaigns. But while heart and determination play a role in politics, elections ultimately are a numbers game. Those numbers no longer add up for Hillary Clinton. After Tuesday's votes in North Carolina and Indiana, Clinton has lost any mathematical chance to win the popular vote. She is 341 delegates shy of the 2025 needed to seal the nomination, and only 211 are up for grabs in the five states that have upcoming elections.

Clinton, however, seems determined to fight on. That is because her party's rules allow for almost 800 "superdelegates" to attend the convention. These superdelegates are picked from the party elite. They are free to cast their votes any way they choose -- and so far, they seem to favor Obama, with 276 leaning his way, as opposed to 271 (including U.S. Rep. Chris Carney) in Clinton's camp.

Their presence in Denver in August could increase the drama factor, something that has been sorely lacking from recent party conventions. So far, drama has been a good thing for the Democrats. Voter registrations and turnout have been breaking records. But there is a point where political drama becomes destructive infighting, and that point is about to be reached.

Does Clinton really want to lose a "popular" vote just to be anointed by a cadre of elites? This sounds hauntingly familiar to the debacle of the 2000 election -- something Democrats have been complaining about for eight years.

Barack Obama is the stronger candidate. He is the clear winner of the small-"d" democratic portion of the Democratic primary. It is time for his historic candidacy to proceed to the next level unimpeded by party machinations.

If there ever was a time to quit while everyone was still ahead, Clinton has reached that moment. She should concede the election and pledge her delegates -- and her tireless support -- to Barack Obama.