Democrats don't want to cut social programs like Medicaid and Medicare. I mean, everybody needs health care so those costs are not avoidable. Unfortunately, health care costs too much because the industry overcharges.
So what does that leave us with? Well mostly military, and the Republicans (and probably many Democrats) only want to increase it. It's over $700B a year now.
If I could wave a magic wand I would:
1) Tweak social security witholding rates to ensure continued solvency. Probably the easiest thing to do.
2) Bring health care costs (ie what providers charge) down to developed world standards.
3) Either raise taxes enough and/or lower defense spending enough to balance the deficit.
It seems simple to me. But it means some people in healthcare and the defense contractors will make less. They would fight it so that's why everything stays the same.