Tony Woodlief:

Those other issues certainly affect a country's safety, prosperity, and greatness. But I've come to believe that a nation that tolerates destruction of innocents deserves neither safety nor prosperity nor greatness. We've descended into barbarism, and it poisons how we treat the elderly, the incapacitated, even ourselves. We shouldn't be surprised, having made life a utilitarian calculation, that more and more humans become inconvenient.

It's certainly true that there are other issues that ought to concern Christians, like the sanctity of marriage, and how we treat the mentally ill, the elderly, and children who have been born. But abortion is, in my view, the touchstone. Get this one wrong and your moral compass can guide you in nothing else.