Repeating a pitch he made this week, President Obama called for a new "grand bargain" for the middle class in his weekly radio/YouTube address, proposing tax reforms and new investments. In the response, Republicans criticized his health care reforms and sought to modify them.

"I'm willing to work with Republicans to simplify our tax code for businesses large and small, but only if we take the money we save by transitioning to a simpler tax system and make a significant investment in creating good, middle-class jobs," Obama said. "We can put construction workers back on the job rebuilding our infrastructure. We can boost manufacturing, so more American companies can sell their products around the world. And we can help our community colleges arm our workers with the skills they need in a global economy-all without adding a dime to the deficit."

At an Amazon warehouse in Chattanooga, Tenn., on Tuesday, Obama laid out his support for corporate tax reform-lowering corporate tax rates in exchange for Republican agreement on ending some business tax exemptions-along with new spending on infrastructure and education.

Read: Obama Offers GOP New 'Grand Bargain'

Republican leaders quickly panned his offer after the president made it on Tuesday.

Over the last week and a half, Obama has delivered a series of speeches seeking to re-frame the economic debate.

"I'll keep laying out my ideas to give the middle class a better shot in the 21st century, and I'll keep reaching out to Republicans for theirs. But gutting critical investments in our future and threatening national default on the bills that Congress has already racked up - that's not an economic plan," Obama said in his weekly address, repeating an attack line used on his recent economic campaign trail. "Denying health care to millions of Americans, or shutting down the government just because I'm for keeping it open - that won't help the middle class."

Republicans, meanwhile, responded in their own address by criticizing the Affordable Care Act-commonly known as "Obamacare"-for incentivizing businesses to stop hiring and suppress weekly hours.

"Small businesses are the backbone of our nation's economy. The last thing we need is yet another obstacle to helping them grow and create much-needed jobs," Sen. Susan Collins, R-Maine, said.

The Affordable Care Act requires employers to provide health insurance if they employ 50 or more people at 30 or more hours per week. The provision was designed to ensure employee coverage from large businesses. The requirement will take effect in 2015, after a one-year delay by the administration. Businesses who don't offer that insurance will face penalties.

Republicans have pointed out that businesses on the cusp will be penalized for hiring more people and giving them more hours of work.

'If you employ 49 workers, there are no fines. But, if you add just one more employee, you're hit with penalties," Collins said. "A school system in my state of Maine is already preparing to track and cap the number of hours that substitute teachers can work to ensure that they don't work more than 29 hours a week. Fewer hours means less money in the teachers' paychecks and more disruption for their students."

Republicans have sought to modify the ACA by shifting the requirement, mandating insurance for employees who work 40 or more hours per week at large businesses, not 30. In her address, Collins promoted her "Forty Hours is Full Time Act," a bill to enact that modification.