WASHINGTON (AP) -- Debates on lowering trade barriers can turn Congress upside down for Democratic presidents promoting such legislation. Business-minded Republicans suddenly turn into allies and Democrats aligned with organized labor can become outspoken foes.
It's a reversal of the usual routine, where a Democratic president can generally count on support from fellow Democrats in Congress and varying levels of resistance from Republicans.
Now it's President Barack Obama's turn to experience such a role reversal.
Already, he's encountering pockets of deep Democratic resistance, especially from manufacturing states, to his efforts to win congressional approval for renewal of "fast track" negotiating authority.
Such tactics help speed the process for major trade agreements by restricting Congress to up-and-down votes -- with no amendments allowed.
Two such trade deals are in the works.