Social Security administers two main programs, the retirement program and the disability program. They are both funded out of the same payroll tax, but that tax is allocated to the two programs in different ratios. Both programs have trust funds that receive part of that allocation, and those funds and the current receipts from the payroll tax pay for the current benefits.
For a variety of reasons, the Social Security Disability Insurance (SSDI) trust fund is projected to go into negative cash flow (more money goes out in benefits than comes in from taxes) in the next year or so. This would mean that beneficiaries would see about a 20 percent cut to their monthy payments. This would be very damaging for many on the program, as it provides the majority of their income and the average payment for an individual comes in right around the federal poverty line for a single person.
The Republicans in the House are attempting to engineer a "crisis" that will allow them to cut both SSDI and the retirement program under the guise of "saving" them. They have passed a procedural rule that will prevent reallocation, a procedure that has been used numerous times by Congress in prior years to solve this issue.
The Democrats have proposed that rather than attempt a reallocation vote, that the two trust funds should be merged, which will allow both programs to remain solvent until 2033. This would protect the SSD program's benefits and prevent both devastating cuts from a shortfall and the creation of a fake crisis that would allow a fiscal cliff-like, last minute "solution" that would potentially lead to permanent cuts, privatizing or perhaps both.
An even better solution would be for the politicians to recognize the essential nature of these programs and adjust the funding to match the reality of the world as it exists today, and not the world that existed 50 years ago.
Source: theweek.com, "The Democrats' brilliant plan for reforming Social Security," Ryan Cooper, May 12, 2015