There is a difference between a moral principle and the implementation of a moral principle.
In other words, just because a handful of people agree on some point of ethics, that is not to say that they will all agree on what to do next. For example, two people may agree that abortion is wrong (a sentiment I share), but that part's easy. The hard part comes when we get to the "therefore...." Should it be made illegal? If so, by whom, the federal government or the states? What about the economic factors that often contribute to abortion, should we address them, too? What happens when a person thinks that one presidential candidate is against abortion but favors an economic policy that could actually further it, while another candidate is in favor of abortion remaining legal, but promises to address and help eliminate the factors that may lead to abortions?
My point? Simply that it's one thing to have a moral opinion, but the real thinking hasn't started yet.
Take the death penalty. Plenty of Christians believe that capital punishment is biblical, but also feel that it is unjustly administered in the United States. What then? Or what about gay marriage? Is there a legitimate distinction between saying that homosexuality is immoral and saying that the government should enact laws that keep gays from getting married? If not, then are we saying that every immoral practice should be criminalized by the state?
Or what happens when one's pro-life principles force him to choose between voting to outlaw murder in one arena but condone it in another? And even if the murder that happens in one arena (say, abortion) is far more widespread than that which takes place in another (like war), is there still room to weigh the practical chances of eliminating the greater versus eliminating the former, and actually play the odds and vote contrarily to one's preferences?
I don't think there are any easy answers to these questions, and therefore I will not pretend to provide them. All I'm asking for is that, amid our pulpit-pounding and rally cries to one cause or another, we take the time to think a little harder than we are accustomed to doing.
Especially before calling our opponent's faith or character into question.