With his career-long trait of unprincipled moral relativism on full display, Focus on the Family chairman James Dobson this week backpedaled on his already-selective moral objections to U.S. Republican presidential candidate John McCain.

McCain is distrusted among independent and liberal Americans for his short temper, reckless impulses, adultery, divorce, remarriage to a wealthy benefactor, exaggeration of his Vietnam War heroism, affinity for anti-Catholic and anti-Semitic religious advisers, and waffling on American liberties including the freedom to serve in the Armed Forces and the freedom of religious and sexual minorities to marry.

Few of those broad moral, religious, and political considerations have mattered to Dobson, however — his moral voice in recent years has become so small and self-serving that it now encompasses only two issues: Sex and authoritarianism.

(By declining to offer moral leadership in matters of personal and global finance, charity, community diversity, cooperation, interfaith relations, human rights, and environmental stewardship, Focus on the Family has effectively advocated the very same “anything goes” morality that it falsely attributes to liberals.)

Dobson has objected to McCain — and threatened to lead a national religious-right boycott — for petty reasons: McCain’s lack of photo-op religious zeal, his weak commitment to criminalize women who have abortions, and his weak commitment for government to find new ways to discriminate against, ostracize, and criminalize same-sex-attracted Americans.

But now Dobson — who seems unwilling to offer a single specific objection to Democrat Barack Obama’s pro-family and national-security policies — finds himself on the political sidelines, demonizing Obama with misleading insults in order to buy back lost influence among the GOP:

“Barack Obama contradicts and threatens everything I believe about the institution of the family and what is best for the nation,” Dr. Dobson said in a statement to The Associated Press. “His radical positions on life, marriage and national security force me to re-evaluate the candidacy of our only other choice, John McCain. I have not endorsed him, but … I have concluded for the first time that I might. If that is a flip-flop, then so be it.”

I can think of several concrete reasons why some people might distrust Obama: his vague plans to fix the nation’s crises in energy, real estate, the deficit, and Middle East conflicts; his pandering to conflicting racial and sexual interest groups; his opposition to gay marriage. But Dobson seems unwilling to say specifically why he opposes Obama, so he insinuates instead that Obama is an enemy of life, family, and security.

Whatever the private reality, Obama’s public image exemplifies progressive faith and political moderation: A calm, confident balance of moral, social, family, military, and human-rights considerations that strives to unite diverse people under a common banner with carefully measured respect for all.

That image is anathema to Dobson, who has devoted his life to promoting the image of Christian faith as proud, authoritarian, hierarchical, exclusive, boorish toward social outcasts, quick to scapegoat, trigger-happy, inconsiderate of consequences, and perhaps worst of all, willing to sacrifice — crucify — the well-being and liberties of others if it will profit fundamentalists or preserve their countless insecurities.