SEATTLE — The American Civil Liberties Union in Washington state filed a lawsuit Thursday on behalf of a Kennewick gay couple denied service at a flower shop for their upcoming wedding. The lawsuit is in response to a March 1 incident in which Barronelle Stutzman refused to provide flowers for Robert Ingersoll and Curt Freed’s wedding, despite the two men being longtime patrons of her shop — Arlene’s Flowers and Gifts in Richland, about 200 miles southeast of Seattle. Thursday’s lawsuit is the second legal action taken against Stutzman. Last week, Washington state Attorney General Bob Ferguson filed a consumer protection lawsuit. Ferguson had sent a letter in March asking her to comply with the law, but said Stutzman’s attorneys responded by saying she would challenge any state action to enforce the law. Her attorney, Justin D. Bristol, has said he expects to take the legal battle to federal court and argue Stutzman’s refusal of service based on the 1st Amendment’s right to free speech.Stutzman was not available at her flower shop Thursday. A message left at Bristol’s office was not immediately returned.While Washington voters legalized gay marriage this past November, protections against discrimination based on sexual orientation were codified in 2006, in one of the first initial pushes to expand civil rights to the gay community.