President Obama called his first solo press conference of the new year Tuesday to defend his $3.7 trillion budget proposal, vowing that the federal government would stop "running up the credit card" while saying he does not want to take a "machete" to federal spending. 

The president acknowledged that the proposal was the first step in a "negotiation process." Republicans hammered the budget blueprint after it was unveiled Monday, with one leading House Republican saying it would be better to pass nothing than to pass the president's latest plan. Though the White House says it achieves $1.1 trillion in deficit reduction over the next decade, Republicans warn that the government would still add trillions more to the national debt in the process. 

But Obama said his administration is making "tough choices" and "significant spending cuts." 

"We're not going to be running up the credit card anymore," he said, adding that he wants to work with both parties to address entitlement spending, particularly when it comes to Medicare and Medicaid, in the years to come. 

He rejected the notion that the recommendations of his fiscal commission, which died in committee last year, had been "shelved" -- saying those recommendations provide a framework for discussion.  

At the same time, Obama said his administration wants to be able to make "key investments." 

"We've taken a scalpel to the discretionary budget, rather than a machete," Obama said. He said his budget "puts us on a path to pay for what we spend by the middle of the decade." 

Still, the budget comes with a combined $7.2 trillion in cumulative deficits over the next decade. Republicans say more cuts must be made to stabilize the debt.