Republicans vow to block an increase in the debt ceiling without spending cuts.
The united states has hit its $14.3 trillion credit limit.
The government says it needs to borrow another $2 trillion to keep paying America's bills.
The House votes on that tonight, but it's expected to fail.
"To get my vote to raise the debt ceiling, for whatever that's worth, my one vote, Medicare will be a part of it," says Senate Minority Leader Mitch McConnell.
Republicans want to save money by turning Medicare into a voucher system.
The government would give seniors money to buy their own health insurance.
The Senate voted that down last week.
Democrats call it the worst of three options.
"Until Mitch McConnell abandons the third one, we are not going to get a budget deficit agreement. It's that simple," warns New York Senator Chuck Schumer.
Medicare is one of the biggest parts of the federal budget, and it's growing.
Democrats and Republicans can't agree on how to deal with that, even though they've reportedly agreed on nearly trillion dollars in cuts elsewhere.
President Obama wants to raise taxes on the rich to save more.
Republicans say that's not an option.