Those GOP "moderates" can't seem to get past their own belief that pro-life conservatives are indeed extreme and so assume it will be easy for Democrats to paint them as such in the election. But most Americans are less likely to view those defending innocent life as extreme than those defending its extermination in the name of women's rights. They are less apt to consider the championship of traditional marriage as extreme than forcing society to sanction, even celebrate homosexual unions.
Interestingly, Democrats instinctively understand the awesome power of social conservatives -- they call them values voters. That's why for the last three or four years we've seen stories every other month or so about the Democrats' "new" efforts to woo values voters. That's also among the reasons those same Democrats have made such a concerted effort to shut out Christian conservatives from the public square under the cover of a church-state separation crusade.
No matter what the polls now show, I believe social liberals like Rudy Giuliani are long shots for the GOP nomination. Even promises to appoint originalist judges won't likely mollify the conservative base, because if you are pro-choice, it's doubtful you strongly believe Roe v. Wade was wrongly decided or that you'll be passionate about overturning it. You'll also be less inclined to disagree with the left's expansive view of the Establishment Clause that effectively suppresses religious liberty in the name of protecting it.
Much of Mitt Romney's difficulties with the base can be traced to its unease with his flip-flop on the life issue. It's not that the base is unforgiving concerning his past views, but that it is not sure his "conversion" is authentic. With the base, trust is as important as the underlying issues.
I admit I'm less certain than I was before 9/11 that it would be virtually impossible for a social liberal to capture the GOP nomination. But "virtually impossible" has only been upgraded to "highly unlikely."
To argue it's more important to have a strong leader in the war on terror than one who will stand up for traditional values is to present a false choice. There are a number of capable, credible and electable candidates out there who are "right" across the spectrum.