Today, the second day of the Perry v. Schwarzenegger trial, opened with continuing expert testimony from Nancy Cott, a Harvard University historian and the author of “Public Vows: A History of Marriage and the Nation.” Cott’s testimony will give the Boies and Olson, pro-gay-marriage side the opportunity to make the argument that marriage is a dynamic institution, one that changes as society does: which is why, for instance, married women can now own property, people of different races can marry, and couples of all sorts can divorce, and why, by implication, it could stretch without breaking to accommodate same-sex couples. Her testimony will also be used to counter the other side’s argument that the state has a legitimate interest in upholding “procreative” marriage.” Today, according to Howard Mintz of the San Jose Mercury, who is live-blogging the trial, Cott testified that “procreative ability has never been a qualification for marriage.” George Washington, “the father of our country,” she said, was likely sterile when he married Martha Custis.