Clinton reaches for Pa. win; Obama says he'll be close

Barack Obama said she would probably win but he hoped to keep it close in Tuesday's voting.

Clinton made her closing arguments Monday for the biggest primary left on the election schedule, running an ad with historic images to ask voters whom they would trust most in the White House during a time of trouble. It's the same tactic she used successfully in the "3 a.m." ad she aired in the closing days of the Ohio and Texas contests last month.

It was the first time a Democratic candidate has used bin Laden in a campaign commercial in the 2008 race for the White House. The terrorist appears along with images from the stock market crash, the bombing at Pearl Harbor, the Soviet threat, the collapse of the Berlin Wall and Hurricane Katrina as an announcer tells voters the political contest is for "the most important job in the world."

"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 Clinton appears on screen.

Obama spokesman Bill Burton said the ad "plays the politics of fear." And he said Clinton is to blame for allowing bin Laden to escape by supporting war in Iraq and diverting the U.S. military.

"It's ironic that she would borrow the president's tactics in her own campaign and invoke bin Laden to score political points," Burton said.

Leaving the negative talk to aides, Obama himself tried to end on a positive note after days of escalating accusations against Clinton. He didn't criticize his rival as he spoke with voters at an outdoor plaza in suburban Philadelphia, where tulips and daffodils bloomed and children played in the background.

"I thought this would be a nice change of pace," Obama said. A bank of TV cameras captured the soft images early enough in the day to ensure that voters would see the images on Philadelphia newscasts the night before the primary.

Pennsylvania's demographics suit Clinton. The state has a higher median age, a higher percentage of whites, a lower median household income and fewer bachelor's degrees than the country overall. These are the voters working-class whites and voters older than 50 who have flocked to her in past contests.