When you look at the current Republican Party and their positions on economics, the poor, civil rights, health care, American helping American, disaster relief, women's rights, immigration, science, technology, jobs, business, education and the environment, I don't believe you can be a moderate and vote for that party. Every current position the Republican Party has is extreme and very far outside of what is considered the "norm". This is the most radical party in my lifetime if you go by their Party Platform, where they are on the issues, the fact they are 90% white and what they did to this country under former President Bush. Then you add in the unearned hatred for the current president. Their talk of secession and support for domestic terrorism. Where does "moderate" fit in? Perhaps in the next generation. But not for at least the next 10 years.
That's the thing: any intelligent person knows that he or she can disagree with any one or multiple element(s) of a party's platform. I'm pro-choice, pro-gay marriage, moderate on gun control, in favor of a path to citizenship ... yet fiscally conservative. I believe in tax breaks for everyone, including ALL businesses, cuts in wasteful spending and a flat tax code. I do not vote for President based on those social issues, because they won't be the ones deciding them. What Republican President is actually going to have an impact on overturning Roe v. Wade?! They've tried for forty years now... Gay marriage? That will be a courts and legislature debate. Period. Obama's "support" of it had no effect on the issue, IMO. The President will have a decent effect on immigration reform, but there are multiple rising Republicans who are just as "enlightened" on immigration reform as many Democrats are, so no contrast there. Gun control? Maybe ... but like I said, I'm pretty moderate on that anyway.
What does that leave me with? A stark divide between the fiscal policies of the Democrats and those of the Republicans. Sure, I probably have more in common with a Moderate Democrat than a Right Wing Republican, and I absolutely hate that those nutjobs have a presence in the GOP right now, but I care enough about the fiscal issues (on which I think the Democrats are just awful) to vote Republican. And I'm still a moderate.
EDIT: If a Democrat came out in support of all those fiscal policies I just mentioned, I'd vote for him or her in a heartbeat ... but they're too dependent on some of their largest voting blocs (working class, those who benefit from government redistribution of wealth, those on government programs, etc.) to ever do that. Hence, I will not be supporting any Democrat any time soon, no matter how crazy some Republicans are.