Rep. Matt Salmon (R-Ariz), the father of a gay son, explained his opposition to gay marriage by saying he hasn’t “evolved to that stage.” He may not be joining same-sex marriage supporters. But he’s adopting their vocabulary. (Remember the evolution of Virginia Sen. Mark Warner, California Sen. Barbara Boxer, and Secretary of State John Kerry, among others.) Now Republicans looking for breathing room on gay marriage are joining in. How did “evolving” become so prevalent? While a Hillary Clinton spokesman did say back in 2003 that “this issue is in a state of evolution,” President Obama gets the credit here. His 2010 comment that on gay marriage “attitudes evolve, including mine,” — followed by repeated White House confirmations that the president was “evolving” — made evolution the verb of choice.