Outspending Hillary Clinton 3-to-1 in Pennsylvania, Barack Obama must win there on April 22 to demonstrate his ability to win big states, said top Clinton aide Howard Wolfson today during a conference call with reporters.

"[Obama is] doing everything he can to win in Pennsylvania, and if he can't, it'll be a serious defeat," said Wolfson. "We all know the road to 1600 Pennsylvania Avenue runs through Pennsylvania."

During the call, Wolfson and T.J. Rooney, Pennsylvania State Democratic Party Chairman, also unveiled the campaign's radio ad responding to the Obama's contention that he doesn't "take money from oil companies."

"What he doesn't tell you is that 'no candidate does ... they cant,' according to the Annenberg Center's Factcheck.org," a narrator on the Clinton spot says. "It's been against the law for companies to donate to candidates for a hundred years."

The Clinton campaign has called on Obama to withdraw the ad in which he makes those comments. "Despite that, he continues to run it," said Wolfson. In response, Wolfson said the campaign was forced to put the radio ad to "set the record straight."

Here's the script for the new radio spot, "Real Life":

In his TV ads, Barack Obama sounds like he'll take on the oil companies.

"I don't take money from oil companies."

What he doesn't tell you is that "no candidate does ... they cant," according to the Annenberg Center's Factcheck.org...It's been against the law for companies to donate to candidates for a hundred years.

Listen to Barack Obama some more.

"Now Exxon's making forty billion dollars a year and we're paying three fifty for gas."

Obama also doesn't mention that he voted for the Bush Cheney energy bill.

It was called a pinata of perks and the best energy bill corporations could buy.

Hillary Clinton voted against that bill.

She's the one who will make the oil companies pay to set up a new strategic energy fund that will cut our dependence on foreign oil invest in new clean energy, and create five million new jobs.

It's time for president who takes on the oil companies in real life, not just on TV.

Hillary Clinton.