Image credit: Matt Rourke/AP Photo

PHILADELPHIA - Stumping today at one of her first solo public campaign rallies of the year, First Lady Michelle Obama didn't utter the word 'Wisconsin' or discuss Democrats' defeat in that state after months of organizing to oust Republican Gov. Scott Walker.

But her message to supporters, in the wake of what transpired a thousand miles from here, could not have been clearer:  the 2012 race is going to be a grinding fight that will require more passion and commitment from Democrats than it ever has before.

"I am not going to kid you: this journey is going to be long, and it is going to be hard, and there will be plenty of twists and turns along the way," Obama told the crowd of 1,100 packed into the National Constitution Center.

"But just remember that's how change always happens in this country. And if we keep showing up, if we keep fighting the good fight. Eventually we get there, we always do," she said.

The first lady implored her audience to take a close look at her husband's record -steady private sector job growth, the resurgent auto industry, health care reform and end to the War in Iraq - and "get out there and remind people."

"We need you to tell them about it, but we also need people to know that all of this and so much more is at stake in November," she said.

"It all boils down to one simple question: will we continue the change we've begun and the progress we've made, or will we let everything we've fought for slip away."

"Convince them with every ounce of energy in your soul to join you in giving a little part of your life each week to this campaign," she said later.

Mrs. Obama attested to her husband's character, calling him an "extraordinary man." And though she never mentioned presumptive GOP nominee Mitt Romney, she suggested the president is the only candidate in the race who understands means to be middle class.

"When there's a choice between protecting our rights and our freedoms, you know where Barack stands," Obama said in an impassioned flourish. "And when we need a leader to make the hard decisions to keep this country moving forward, you know you can count on my husband, your president."

Mrs. Obama's visit to Pennsylvania, her third of the year, underscores the importance of the state to her husband's electoral road map.

President Obama carried Pennsylvania in 2008 by 11 points over John McCain - 55 to 44 percent - and its 20 electoral votes would be a significant pick-up on the path to 270.

A new poll by Franklin & Marshall College shows Obama leading Romney by 12 points here, 48 to 36 percent, with 12 percent of voters undecided.

"The president enjoys significant advantages over Mitt Romney in his personal popularity and most voters believe he is better prepared to handle the presidency even though they are ambivalent about some of his major policy initiatives," the poll said in a press release.   The survey, conducted May 29 to June 4, has a margin of error of 4.8 points.

But Democrats aren't taking anything for granted, especially with Obama's underwater favorability rating and weak numbers on his handling of the economy in the latest poll.

Sixty-one percent of voters in the Franklin & Marshall poll said Obama has done only a fair or poor on the economy; 38 percent said good or excellent.

"In the end this could come down to the last few thousand people that we register to vote," Mrs. Obama said today. "It could all come down to those last few people we help get to the polls on November 6."

Elaine Tomlin, a neighborhood team leader for Obama's campaign, said the First Lady's message is exactly what Democrats in Pennsylvania need to hear.

"We've been phone banking since July of last year. We're a big team in Philly and we know we're going to need an army with the obstacles put out there with the voter ID law," Tomlin said.

"We know what we have to do. Even though the GOP has the dollars, we have the grassroots campaign. And it's one person, one vote. It's our goal to have turn out be very high," she said.

The first lady is back on the campaign trail tomorrow with another grassroots rally in Woodbridge, Va.