"I don't like your politics." According to an FBI affidavit, a man said words to that effect before pulling a handgun and opening fire while trying to gain access to the Washington, D.C., headquarters of the Family Research Council.

In a welcome sign, leaders across the political spectrum condemned the Aug. 15 shooting, which wounded a building manager who confronted the gunman.

In addition to Christian conservative allies of FRC, those who spoke out included Republican presidential candidate Mitt Romney, President Barack Obama and liberal groups such as the Human Rights Campaign and the DC Center for the LGBT Community - where the alleged shooter worked as a volunteer less than two miles from the FRC headquarters.

Declaring violence off-limits means we're recommitting to live peacefully with our deepest differences while pursuing consensus on how to organize life together in this great country.

While that resolve is fresh in the mind, this is an important moment to consider the character of our public conversation about sexuality and marriage. We await a likely announcement this fall from the U.S. Supreme Court that it will take up cases involving marriage, on the heels of what has turned out to be a very hot summer of intolerance toward traditional views of marriage.

Since June, protesters have targeted University of Texas sociologist Mark Regnerus, author of a peer-reviewed study showing some negative outcomes for young adults whose parents had same-sex relationships.

Such findings conflict with those stated in federal Judge Vaughn Walker's opinion overturning California's Proposition 8. In striking down that popular vote for marriage as the union of a man and a woman, Walker asserted that children of same-sex parents show no difference in outcomes from peers raised by a mother and father who are married.

Regnerus' "New Family Structures Study" suggests otherwise. It improves on prior research with a large, nationally representative sample. Demographer Cynthia Osborne, in a critical review published in the same issue of the journal Social Science Research, concluded "the Regnerus study is more scientifically rigorous than most of the other studies in this area."

That didn't stop the Human Rights Campaign and the Gay and Lesbian Alliance against Defamation from denouncing it as a "flawed, misleading, and scientifically unsound paper that seeks to disparage lesbian and gay parents." An assistant editor at The New Republic suggested this study should "mark the beginning of the end of Mark Regnerus's credibility with respectable news outlets."

Then came the Chick-fil-A flap in July. Dan Cathy, president of the privately held company, was quoted in a Baptist Press interview as supporting the "biblical definition of the family unit." Expressing outrage, big-city politicians from Boston to Chicago to San Francisco threatened to bar the chicken franchise from their neighborhoods.

The cruel summer simmered on. The day before the FRC shooting, the Human Rights Campaign's website posted a blog headlined "Paul Ryan Speaking at Hate Group's Annual Conference" - a reference to FRC and its Values Voter Summit. Shockingly, when the website put up a statement condemning the shooting, its "hate group" post was four entries below.

"Human Rights Campaign isn't responsible for the shooting," liberal columnist Dana Milbank writes in The Washington Post. Nor should the Southern Poverty Law Center (which originally applied the "hate group" label to FRC) "be blamed for a madman's act," he adds.

"But both are reckless in labeling as a 'hate group' a policy shop that advocates for a full range of conservative Christian positions, on issues from stem cells to euthanasia," Milbank writes.

Milbank disagrees with FRC on homosexuality and marriage. "But it's absurd," he says, "to put the group, as the law center does, in the same category as Aryan Nations, Knights of the Ku Klux Klan, Stormfront and the Westboro Baptist Church."

It sure is. Tolerance doesn't shun those who support traditional marriage. To marginalize as illegitimate those whose research or comments support marriage as the union of one man and one woman is a disservice to debate and social harmony.

Even before the FRC shooting, this summer's string of uncivil responses fell far short of the tolerant tone we'll need to navigate our differences on this issue.

Thankfully, the shooter - whose backpack also contained a box of ammunition and 15 Chick-fil-A sandwiches, authorities said - got no further than Leo Johnson, the building manager. Johnson took a bullet to the arm before tackling the assailant. He's now on the road to recovery.

Let's hope the wounds to America's civil discourse this summer mend soon, too.