Sen. Barack Obama’s decisive primary win in North Carolina and narrow loss in Indiana Tuesday pushed the Illinois senator closer to the Democratic presidential nomination. But final resolution of his extended battle with Sen. Hillary Clinton hangs on three distinct factors:

• The 267 uncommitted superdelegates whose votes likely will determine the winner;
• Key primaries in West Virginia, Kentucky and Oregon in the next two weeks;
• A crucial May 31 meeting of the Rules and Bylaws Committee of the Democratic National Committee to rule on the validity of contested and uncounted primary votes in Florida and Michigan.
  

Here’s what Tuesday’s primary results mean for the campaigns:

1. For Sen. Hillary Clinton.

The calendar and ever-smaller number of unpledged delegates are unforgiving. Clinton could not capitalize on the momentum after a 9 percent victory in Pennsylvania April 22. Instead, she was swamped, losing by 14 percent and 200,000 votes in North Carolina while scoring a very slim victory in Indiana. Clinton continued the high-energy strategy that had worked in Pennsylvania—an underdog, populist message that resonated in rural and suburban areas of Indiana and in the blue collar corners of North Carolina. But it lost some of its steam.

Looking forward, lack of campaign funds and lack of time are the Clinton campaign’s two biggest challenges. Clinton’s less-than-enthusiastic speech to her supporters on primary night underscored the harsh mathematical reality: The winner needs 2,025 delegates. She has 1,692. Clinton trails Obama by 150 delegates, but there are only 217 pledged delegates at stake in the remaining six primaries. Party rules mandate that delegates be allocated in accordance with the candidates’ share of the votes, which makes it virtually impossible for her to overtake Obama without a surge of superdelegate commitments.

2. For Sen. Barack Obama.

Last month Obama predicted he would take North Carolina while Clinton took Pennsylvania. Indiana, he said, would be the tie-breaker. Tuesday’s vote was close enough that Obama can claim a draw. He was nagged by the firestorm following the controversial statements of his former pastor Rev. Jeremiah A. Wright Jr. But he gained traction with a retooled pitch to blue collar workers.

Obama faces his own challenge with primary math. Victories in states where he’s leading—Oregon, Montana and South Dakota—will leave him about 150 delegates ahead of Sen. Clinton, but about 100 short of the 2,025 he needs for the nomination.

3. For Sen. John McCain.

McCain’s victory lap continues. With the Republican nomination secure, is he making the best use of his time? McCain has bulked up his campaign staff, continued raising funds and stumped his way across the Midwest. He has spent much of the campaign cash he raised last year and is concentrating on replenishing his coffers. It’s no small task. Already this month, McCain is scheduling finance receptions and finance luncheons in seven states from New York to California. (Tickets range from $1,000 to $3,000, with a $10,000 to $25,000 per-couple price tag for photographs with McCain.)

4. Keep your eye on the ball.

The key number for Democrats is 2,025—the number of delegates a candidate needs to win the nomination. After Indiana and North Carolina, Obama has 1,842 delegates to Clinton’s 1,692. According to www.RealClearPolitics.com, a nonpartisan website, Obama’s total includes 257 so-called superdelegates. For Clinton, that tally includes 271 super delegates. Superdelegates are Democratic office holders and party officers who are given special stature in the Democrats’ selection process—the wise leaders and statesmen who can exercise discretion in an inconclusive or controversial contest. Of the 795 superdelegates, 267 have not endorsed either candidate. It’s these superdelegates who will determine the Democratic nominee. Pressure on them is mounting daily.

5. The 50+ election.

Of the Indiana primary voters, 49 percent were over 50; they supported Clinton, according to exit polls conducted by the polling combine financed by major networks and news services. Some 72 percent of the 65-plus voters supported Clinton, her margin of victory.

In North Carolina 55 percent of the voters were over 50 and they split. Of those voters between 50 and 64, Obama captured 52 percent. Clinton won 57 percent of the over 65 voters.

In both states, voters identified the economy, the Iraq war and health care as their top concerns. In Indiana voters who identified Iraq as the top issue preferred Obama; those identifying the economy and health care preferred Clinton. In North Carolina Obama won among each group.

6. Indiana. Is the squeaker a game-changer?

Clinton won with a 2 percent margin and took 36 of the 72 delegates, with 6 still undecided. Indiana was a must-win state for Clinton, and she did—barely. An Obama victory there would have complicated her effort to continue the campaign. As an Illinois senator, Obama is well known in Indiana, particularly in the northwest corner of the state (the Chicago television market). He ran well in university towns and in Indianapolis. The soft economy and 5.2 percent unemployment helped Clinton. But Indiana remains a GOP state. Republicans have won every presidential election in Indiana but one since Franklin D. Roosevelt’s last election in 1944.

7. North Carolina, a decisive victory.

Obama won by 14 percent and took 63 of the 115 delegates. About one-third of the Democratic voters were African American, and by a 92–6 percent margin voted for Obama. That was more than enough to withstand a statewide blitz to more than 50 small towns in the state by ex-President Bill Clinton. North Carolina is an increasingly urbanized state whose population is growing by 200,000 a year, mostly white professional retirees. Is this a dynamic that puts North Carolina in play in the November election? Jimmy Carter was the last Democratic presidential candidate to win North Carolina, in 1976.

8. Next up.

While intensifying their pitches to uncommitted superdelegates, Obama and Clinton will return to the campaign trail for three important primaries in the next two weeks—West Virginia (28 delegates) on May 13, and Oregon (52 delegates) and Kentucky (51 delegates) on May 20.

With her well-practiced populist message, Clinton has an early lead in West Virginia and Kentucky, while Obama is leading in Oregon polls. The last three primaries are in Puerto Rico (55 delegates) on June 1 and in Montana (16 delegates) and South Dakota (15 delegates) on June 3.

The Democratic Party Rules and Bylaws Committee meets May 31 to discuss delegates from Michigan and Florida, where primary votes were disallowed when state officials held their primaries in February and March, earlier than allowed. Neither candidate campaigned in Florida or Michigan, but Clinton has argued that votes should be counted. Although the primaries were declared nonbinding, she outpolled Obama in Florida and won in Michigan, where she was the only named candidate on the ballot. 

9. The money race.

Presidential candidates have broken all fundraising records this year, raising $800 million, and the primaries are still not over. Obama has tapped millions of new contributors. By March 31 he had raised $234.7 million and spent $183.7 million. Clinton’s campaign raised $189.1 million and spent $157.4 million. Campaign funding remains a weakness for Clinton, who continues to trail Obama in funds raised and spent. At the end of March, her campaign was also $15 million in debt, compared to Obama’s debts of $662,000. Sen. John McCain has raised $76.7 million and spent $65.1 million. He owes $707,000.

10. The last word.

“The way the loser loses will determine whether the winner wins.” Democratic Rep. Rahm Emanuel of Illinois, who has not endorsed either candidate yet, in a New York Times interview.