Washington Attorney General Rob McKenna leads his Democratic challenger by seven points, a poll indicates. McKenna-who is seeking a second, four-year term- leads Democrat John Ladenburg 49 percent to 42 percent, according to a SurveyUSA poll released this week. The poll found that 23 percent of Democrats will cross party lines to vote for McKenna, a popular Republican. Meanwhile, 11 percent of registered Republicans said they plan to support Ladenburg, the Pierce County executive.