Polls show a tightening race for the Democrats in Pennsylvania.
The latest numbers in one poll show Sen. Hillary Clinton with a 47 to 42 percent lead over Sen. Barack Obama in Pennsylvania.
That's closer than it was two weeks ago, when Clinton had a double-digit advantage.
Obama is campaigning hard in the Keystone State, which holds its presidential primary later this month.
"What I oppose - and what I will always oppose - are trade deals that put the interests of Wall Street ahead of the interests of American workers. That's why I opposed NAFTA," Obama said at a meeting of the Pennsylvania AFL-CIO.
Obama and Clinton have spent weeks arguing over which one of them did or didn't oppose the North American Free Trade Agreement, a deal with Mexico and Canada that was struck during Bill Clinton's presidency.
As for voter demographics, the New York senator is well ahead of Obama among the state's white voters, 59 percent to 34 percent, while Obama gets nearly three of four black votes.
She leads among women, while the two run even with men. As usual, the Illinois senator does best with younger voters, while Clinton leads among older ones.
And despite her diminishing numbers in Pennsylvania, Clinton is splitting her day there with nearby Indiana where the Democrats host their primary May 6.
Source: The Associated Press