By Jeff Mason

WASHINGTON (Reuters) - Buoyed by a victory over healthcare reform but stung by poor economic data, President Barack Obama will try to rev up his re-election campaign on Thursday with a bus tour designed to appeal to struggling blue-collar workers in key battleground states.

Obama will spend two days visiting cities in Ohio and Pennsylvania, states that could prove critical to his ability to garner the number of electoral votes needed to beat Republican Mitt Romney in the November 6 election.

The president, a Democrat, is launching his first bus tour of the 2012 campaign against a backdrop of mixed poll numbers, fundraising challenges, and outside threats to an economy that could derail his chances of re-election.

An average of polls by RealClearPolitics shows the president ahead of his Republican rival by a tight 2.6 percentage points in Ohio and nationwide.

Obama is polling particularly well with women and Hispanics across the country, but working-class men are up for grabs. The Ohio trip seemed aimed at least in part at shoring up support in that demographic.

"It's a race for blue-collar men," said Democratic strategist Bud Jackson, noting that that group was especially affected by the sluggish economy and especially receptive to negative campaign messaging that the president has failed to turn around the economy.

"The ability of the president to win over blue-collar men is more tied to the reality of the moment: are jobs being created and do people feel more optimistic? For him, the proof is somewhat in the pudding."

This may not be the best week to find that proof.

Data released on Monday showed U.S. manufacturing activity contracted in June for the first time in nearly three years, and monthly jobless figures on Friday are expected to show unemployment unchanged at 8.2 percent.

Obama got a political bump from the Supreme Court's decision last week to uphold his healthcare law, but economic uncertainty in Europe and at home remain a major vulnerability. Romney is pressing his case hard that the president has not done enough to boost the economy.

Obama frequently stresses that the economy is not improving rapidly enough while emphasizing that his policies helped avoid another recession and saved the U.S. auto industry from extinction. Continued...