The cross-examination of anti-gay marriage witness David Blankenhorn by attorney David Boies turned into quite the sparring match at the Proposition 8 trial in San Francisco on Tuesday.

According to San Jose Mercury News reporter Howard Mintz, the cross-examination turned into “more than an hour of nearly uninterrupted skirmishing” and “degenerated into an argument in open court.”

It sounds as if Boies, who's known to be a tough interrogator and wants to overturn Prop. 8, was doing his job.

Blankenhorn, founder of the Institute for American Values, testified that marriage is an important institution for reasons that mostly revolve around procreation.

Proposition 8, according to Blankenhorn and Prop. 8 defense attorneys, was therefore necessary to keep gays and lesbians from mangling “traditional marriage.”

Unsurprisingly, Boies took exception to Blankenhorn's testimony, and the two men clashed in court.

Boies had good reason to hit Blankenhorn hard: The witness spoke directly to a key point of the defense's case that marriage helps biological parents, who may suddenly find themselves with child, create stability for their kid.

As we've mentioned before, that kind of legal logic may sound crazy, but it's been a winning argument for anti-gay marriage lawyers in the state courts of Indiana and New York.

During cross-examination, Boies forced Blankenhorn to acknowledge that he did not know of any studies that showed kids are somehow more harmed by having gay parents.

The lawyer also challenged the witness's expertise: Blankenhorn has a master's degree in labor history and never taught marriage-related courses.

Cross-examination of Blankenhorn continues today.

Blankenhorn may be the last witness for the defense. If so, pro-Prop. 8 attorneys will rest their case and closing arguments will take place in a few weeks.

Contact Patrick Range McDonald at pmcdonald@laweekly.com.

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