The idea that Anderson hurt Carter is ludicrous. One only has to see what happened in 1984 to prove it. Once you filter out the states in the South that became Solid Republican as of the 1984 election (states in which Anderson did very poorly in 1980, but which Carter held on to because he was a Southerner), the states that Anderson did well in swung towards the Republicans more than those in which he did poorly.
The Carter presidency was a wreck. John Anderson (I voted for him because I recognized Carter as a disappointment and could not stand Reagan) made little difference. It's possible to say that the 1980 election would have been close if one could have added the votes of Carter and Anderson -- but that would have required a much-better Presidency of Jimmy Carter.
Maybe -- but just look at how the states that voted most strongly for Anderson eventually voted. 25 of the states (and DC) gave independent candidates (mostly Anderson) more than 7% of the total vote. 22 of those states (and DC) -- exceptions were Arizona, North Dakota, and Nebraska) went for Barack Obama in 2008. Maybe "Rockefeller Republicans" are the sophisticated Republican voters largely in the suburbs... and after several years of the GOP degenerating into a cadre of primitive, superstition-pandering, bellicose pols the sorts of people who might have voted for a Nelson Rockefeller in the 1970s or 1980s have drifted away from the GOP.
It is questionable whether Gerald Ford was less liberal than Jimmy Carter.
We will never know.
Which could be very irrelevant soon should Rick Santorum lose the Pennsylvania primary.
If, if, if. Running against President Obama on the assumption that President Obama is a weak leader and a left-wing extremist may itself be a disaster.