Republicans say such changes are an essential part of any big deal. And Obama previously has been open to a number of reforms that irk the liberals, such as raising the retirement age of Medicare, means-testing and adopting an inflation calculation, known as chained CPI, for Social Security.

Inevitably, if there is an agreement on a big deal, Democrats will have to get on board for it to pass. But the 2012 election brought in new Democratic members of the House and Senate who are more liberal and more outspoken, strengthening the left wing of the caucus.

One hundred and seven of the 200 House Democrats signed a letter to Obama threatening to vote “against any and every cut to Medicare, Medicaid or Social Security benefits — including raising the retirement age or cutting the cost of living adjustments that our constituents earned and need.”

Instead, they want the White House to “rely on economic growth and more fair revenue-raising policies to solve our fiscal problems,” like getting rid of subsidies for big businesses and raising taxes on the wealthiest Americans.