Every so often I have to acknowledge Matt Yglesias as an unusually perceptive blogger. He is now saying that the health care reform in the U.S. is not only a big win for Obama and other Democrats, it is almost unthinkable that it will ever be substantially repealed.
Running to the right with Goldwater lost the Republicans the 1964 election, and paved the way for the Democrats who had won a landslide to add the Great Society to the New Deal. Later Republican victories did nothing to roll back any of that--any more than Eisenhower had rolled back, or tried to roll back, the New Deal itself. (Eisenhower quite deliberately expanded Social Security to include 10 million more workers, and increased the payments that retired workers would get).
In the recent health care debate, Republicans were inclined to identify Medicare, now including Bush Junior's very expensive prescription drug benefit, as a sacred trust. They are somewhat more open to "reforming" Social Security in order to save money, but no one really thinks they have the votes for that. (Democrats seems more willing to find savings in Medicare than in Social Security; perhaps Medicare is more focussed on issues that are truly not your fault, and this makes Republicans more friendly to it; Democrats resist the distinction between the deserving poor and the undeserving poor, but want to go after Medicare because the cost really is going up dramatically).
Republican Paul Ryan"s plan seems to involve keeping Medicare intact for those over 55, more so than Social Security.
Attempts to keep welfare payments down, add work requirements etc. are more associated with Republicans than Democrats (conservatives more than others in Canada); but once in place, such limits and requirements are hard to abolish. One might say there is a bipartisan desire to prevent welfare from being or appearing more generous than low-paid, hard jobs.