President Barack Obama is leaving nothing to chance in his push to get a major fast-track trade bill through Congress.

He headed to Capitol Hill at 9:30 a.m. for a meeting with House Democrats to rally reluctant members to support the legislation ahead of a vote expected later today.

Lawmakers said the White House has pushed harder on trade than any legislative issue since the health-care reform push during his first year. After keeping trade on the back burner, Obama joined forces with business-friendly Republicans after the midterm elections in pursuit of a rare bipartisan deal and launched a fierce effort to win support from his usual Democratic allies over the intense opposition of labor unions.

A victory would propel Obama toward success on a legacy-building issue in his final years in office, but a loss would be a major embarrassment for a president who has invested significant personal credibility and political capital in the fight.