In a response to Marc’s Presidential primary post from yesterday, commenter Brassband sums up the “electability” case being made for Mitt Romney…

To be elected President, a Republican has to be able to appeal to the “persuadable middle” seven or so percent of voters in about seven or eight key states…
Romney’s not perfect, but he’s worlds better than Pres. Obama!

I suspect there are some people who might have felt comfortable with this line of reasoning pre-Barack Obama, or maybe pre-George W. Bush, but who have serious reservations in the year 2012.
It has been observed that Franklin Delano Roosevelt’s New Deal became a permanent piece of American governance, only after Republican President Dwight Eisenhower accepted that he would govern within its framework, and not try significantly to alter or reduce it. Likewise, Lyndon Johnson’s Great Society became permanent when Richard Nixon chose to administrate its massive expansion of government, rather than scale it back. And once Jimmy Carter’s you-got-a-problem, I got-a-program polyglot of new cabinet agencies survived the Republican administration of Ronald Reagan that followed, despite Republican talk that has never ended about shutting down agencies like the Department of Energy or the Department of Education, no Republican President or Congress has come close to doing so.
Mitt Romney is having problem gaining a lock on Republican support because many Republican voters are aware of this dynamic. They are worried — rightly so, in my humble opinion — that a Mitt Romney administration might choose a basic governing philosophy of “managing” the structural foundation for a Euro-style soft-socialism that Barack Obama has laid, making it permanent in the process, even if that is not the intention. It’s not difficult to imagine the message of the first few months of the Romney administration being, we’re in an economic crisis now so we’ve got to work with the government as it is; but don’t worry, in a few years, or a few decades, when things are back to normal, then we’ll form a study commission to propose a super-committee to discuss passing a timetable to begin to slow the automatic annual growth of government. For a possible likely outcome, see the results of the Eisenhower, Nixon or Reagan administrations on domestic policy.
If candidate Romney wants to increase his support amongst Republicans, he needs to be more convincing than he has been so far that this won’t be the case.