Neither Franklin Roosevelt on Social Security nor Lyndon Johnson on Medicare was wedded to any of the particulars of those programs — only the principle of guaranteed support from the government.
The road ahead is paved with compromises that many Democrats won't like. The president will stick to his refusal to negotiate with Republicans who want to hold an increase in the debt ceiling hostage to spending cuts. But he will have to negotiate over the sequester — the $1.2 trillion in cuts to defense and domestic programs scheduled to take effect in two months.
Decoupling the debt ceiling from the sequester will be daunting, if not impossible. Even if Obama succeeds, he will have to agree to cuts to entitlements or discretionary programs, a course many liberals oppose. They haven't forgotten how Obama almost betrayed their interests in the failed "Grand Bargain" talks in July of last year.
If liberals are disappointed in Obama's fiscal-cliff deal, imagine how they will feel in late February when he starts making tough choices on spending cuts. Liberals need to think harder about what their own long-term deficit reduction plan would be. Raising more revenue is necessary. It's not sufficient.