Union helps Obama with gas price ad

Barack Obama, whose campaign is already swamping Hillary Clinton on Pennsylvania airwaves, is getting some more help today from one of the most important unions supporting him.

The Service Employees International Union launched an ad that hits the hot-button issue of record gas prices and highlights Obama's energy proposals and his stand of not accepting campaign cash from federal lobbyists.

In the ad, motorists at the pump and in the cars complain about how much it is costing to fill up and about how too many politicians are in the pocket of Big Oil.

"Pennsylvania families like mine are hurting every time they fill up the tank, and voters need to know there’s one candidate in this campaign who will take on the oil and gas companies and do something about it,” SEIU member Elaine Oley, one of those in the ad, said in a statement. “Barack Obama cares about us and he will bring the change we need.”

SEIU members also plan to hand out leaflets at a Philadelphia service station this afternoon.

In a conference call with reporters today, the Clinton camp repeated a refrain that with Obama outspending Clinton, he should do well in Tuesday's primary -- and if he doesn't, that should raise more questions about his electability in November. Clinton leads by single digits in most polls.