hillaryclintonbarackobama.jpgWASHINGTON (AP) _ One day before today’s critical Pennsylvania primary, Democrat Hillary Rodham Clinton was battling to cement her lead with the state's electorate _ older, whiter and more female than the United States as a whole _ as she joined rival Barack Obama in blanketing the state with attack ads.

Obama predicted Monday that Democratic presidential rival Hillary Rodham Clinton would get the critical victory she needs in today's Pennsylvania primary, but said his goal is to keep it close.

“I'm not predicting a win,'' he told Pittsburgh radio station KDKA. “I'm predicting it's going to be close and that we are going to do a lot better than people expect.''

Clinton could use a big win in Pennsylvania to keep her candidacy afloat, but aides tried to downplay expectations Monday, insisting they would be grateful for a single-digit win.

While the former first lady began the race with a hefty 20-point lead in several polls in the state, Obama's extensive campaigning and heavy ad buy have significantly cut into her lead.

The latest Quinnipiac University Poll showed Clinton leading Obama 51-44 percent in Pennsylvania, an increase of 1 percentage point from a week ago. The survey showed Clinton's strength was greatest among women, white Catholic and older voters.

The two candidates had packed schedules on the eve of the contest. It comes after a six-week break in voting allowed them to spend more time in Pennsylvania than in any state since the primaries and caucuses began at the first of the year.

Both candidates planned final appearances in Pennsylvania's largest urban centers _ Pittsburgh and Philadelphia.

Clinton also released a new television ad summarizing her closing argument.

“You need to be ready for anything, especially now, with two wars, oil prices skyrocketing and an economy in crisis. Harry Truman said it best, `If you can't stand the heat, get out of the kitchen.' Who do you think has what it takes?'' the announcer says at the end, as an image of Clinton at a rally appears. Obama's campaign said the ad appealed to people's fears.

Both candidates started Monday in Scranton, a heavily Democratic working-class area of northeast Pennsylvania that is struggling economically.

Campaign fundraising figures released Sunday showed Obama holding on to his massive advantage, with $41 million raised in March and $42 million available to spend against Clinton this month.

Clinton reported raising $20 million in March and had $9 million for the primary available at the beginning of April. But she also reported debts of $10.3 million, putting her in the red.

Republican nominee-in-waiting John McCain continued a remarkable rebound. He was broke at the time of the first primary in New Hampshire, but came back to run his Republican rivals out of the race. His March report showed he raised $15.2 million and had $11.6 million in the bank, the best fundraising performance of his campaign.

On Monday, McCain campaigned in Alabama, where he recalled the bloody beatings of civil rights marchers in Selma in 1965 as he began a weeklong tour of communities he said suffer from poverty and inattention from presidential candidates.

Last year, Obama, Hillary Clinton and former President Bill Clinton visited Selma to mark the anniversary of the “Bloody Sunday.''

McCain spoke to a crowd of about 100 people who were mostly white although, as the campaign noted, Selma's population is 70 percent black. Black voters have traditionally sided with the Democrats, and overwhelmingly support Obama this year.

Asked about the makeup of the crowd, McCain said: “I am aware the African American vote has been very small in favor of the Republican Party. I am aware of the challenges, and I am aware of the fact that there will be many people who will not vote for me, but I'm going to be the president of all the people.''

In Pennsylvania, the Democratic rivals accused each other in ads of being beholden to special interests.

“In the last 10 years Barack Obama has taken almost $2 million from lobbyists, corporations and PACs. The head of his New Hampshire campaign is a drug company lobbyist, in Indiana an energy lobbyist, a casino lobbyist in Nevada,'' said a new Clinton commercial.

Obama responded with his own tough message, an ad saying he “doesn't take money from special interest PACs or Washington lobbyists _ not one dime.'' Clinton does, it added, and accused her of “eleventh-hour smears paid for by lobbyist money ….''

Aides in both campaigns said Obama was outspending his rival by at least 2-1 on television ads in the state.

With just nine pre-convention contests remaining after Pennsylvania, it appeared mathematically impossible for either candidate to gather the 2,025 elected delegates needed for nomination going into the party convention in August. That leaves the nomination in the hands of so-called superdelegates, the nearly 800 party officials who can vote for either candidate regardless of state primary or caucus results.

The Pennsylvania vote will apportion 158 delegates to the August Democratic national convention, but the party's rules for apportioning those delegates mean that even a big victory will likely do little to close Obama's overall lead.

Clinton goes into the Pennsylvania primary having most recently won the popular vote in the delegate-heavy states of Texas and Ohio, but Obama leads nationwide in delegates selected in primary elections and state caucuses, in the popular vote and the number of pre-convention state contests won.

Overall, including the nearly 500 superdelegates who have committed to one of the Democrats, Obama leads 1,646 to 1,508.