(CNN) – First lady Michelle Obama, making campaign stops in Nebraska and Iowa on Tuesday, boosted her husband's credentials while appearing to make small contrasts with his likely rival Mitt Romney, lauding President Barack Obama's core set of values and relaying stories of his modest upbringing.
Appearing alongside Warren Buffett in Omaha, Nebraska, Michelle Obama touted the White House-backed provision named for the billionaire investor, which would place a minimum 30% tax on Americans making more than $1 million a year. The "Buffett Rule" was blocked in the Senate last week.
In explaining the president's commitment to helping Americans who are struggling, the first lady harkened back to Barack Obama's upbringing.
"See, believe me, what you have to know is your president, Barack, he knows this," Michelle Obama said. "He knows this all too well. He understands these issues because he's lived them. He was raised by a single mother who struggled to put herself through school and pay the bills."
While not mentioning Romney explicitly, her reference to the economic struggles of her husband drew an implicit comparison with the Republican candidate, who has built a fortune estimated to be between $85 million and $264 million. Romney's father also enjoyed financial success, becoming the president of American Motors and then the governor of Michigan.
Many political observers have questioned whether Romney, given his wealth, will be able to connect with middle class voters. In her speech Tuesday, Michelle Obama emphasized her husband's ability to connect, given his experience.
"Believe me, Barack knows what it means when a family struggles," Obama said. "Believe me, he knows what it means when someone doesn't have a chance to fulfill their potential, and how much that hurts. Those are the experiences that have made him the man and the president he is today."
Speaking later in the day in Iowa, the first lady spoke of her husband's core set of values – something Romney's opponents have consistently claimed the former Massachusetts governor lacks.
"As president you can get all kinds of advice from all kinds of people but at the end of the day when it comes time to make a decision, all you have to guide you are your values and your vision and your life experiences," Obama said. "In the end when you're making those impossible choices, it all boils down to who you are and what your stand for. And we all know who my husband is."
The first lady went on to again detail her husband's modest upbringing, mentioning he was the son of a single mother who struggled to balance family obligations and coursework in college.
The Republican National Committee, which began a joint fundraising committee with Romney's campaign in early April, released a statement coinciding with the first lady's trip to Iowa.
“While Team Obama rolls out surrogates and campaign pageantry, Iowa voters have become disenfranchised with 3.5 years of President Obama’s broken promises and failed policies," RNC Spokesman Ryan Mahoney said. "Whether it’s Iowans fleeing the Democratic Party in droves, dismal polling, or sweeping Republican victories since Obama took office, Iowa has shifted away from Obama and no amount of campaign events can change that fact.”