Obama, Clinton start final push in bids for nomination; Pa. primary Tuesday

WASHINGTON -- Finally for the Democrats, the homestretch.

The last 10 contests of the presidential race could make Barack Obama the party's nominee or breathe new life into Hillary Rodham Clinton's candidacy. It starts Tuesday.

Leading in the popular vote, the number of states won and pledged delegates, Obama had hoped to wrap up the nomination earlier in the spring to begin the general election campaign against Republican Sen. John McCain. But Clinton won the last major primaries in Ohio and Texas on March 4 and has vowed to stay in until the party's convention this August in Denver.

Since neither candidate will likely finish with enough delegates to clinch the nomination, both candidates are wooing "superdelegates" -- elected officials and party activists who may back any candidate they wish.

Obama is counting on superdelegates to back the winner of the popular vote and pledged delegate count, a notion even some Clinton supporters agree with. He also figures prominent Democrats would be loath to deny the nomination to a black man who leads in delegates and votes. Clinton is hoping to close the gap with Obama in the final contests and persuade superdelegates that she would be the stronger general election candidate against McCain.

The largest of the remaining states, Pennsylvania, appears tailor-made for Clinton even as polls show her once commanding lead narrowing to single digits. Most analysts predict a win for the former first lady on Tuesday; a loss would effectively doom her candidacy. Even a narrow Clinton victory would be viewed as a tactical triumph for Obama.

While Pennsylvania's economy may not be as fragile as that of neighboring Ohio, which Clinton won by 9 percentage points, the state has seen a similar erosion of its manufacturing base and a loss of thousands of blue-collar jobs.

Pennsylvania also has a large white, working-class population and other groups that Clinton has attracted. It has the third oldest population of any state and is home to a significant number of ethnic Catholic voters. The state's politically savvy governor, Ed Rendell, backs Clinton.