In the latest Rasmussen Reports poll of Washington state's Senate race, Democratic U.S. Senator Maria Cantwell leads Republican Mike McGavick 49% to 36%. The rolling average of our last three polls shows Cantwell with a 50% to 36% lead.

Beginning this month , Rasmussen Reports is releasing data for a three-poll rolling average on our state election polls. Used in conjunction with individual survey results, this tool will help determine whether shifting poll results are due to changes in the race or are merely statistical noise.

The data shows a slight but steady decline in Cantwell's support. She earned 52% of the vote in our first poll of the race, slipped to 51% in the next two, then slipped further to 50% in February and 49% in March. In all cases her lead has ranged from 13 to 15 points.

Whether the dips in Cantwell's numbers reflect a lasting trend or are merely statistical noise remains to be seen.

McGavick, a former Safeco Insurance executive, earned 37% of the vote in our first two surveys and has been holding steady in the last three polls at 36%.

Washington is a "blue" state that John Kerry won by seven points. But in 2004 it was also the scene of a controversial double recount in the gubernatorial election that ultimately favored the Democratic candidate by 129 votes. A few years earlier, Cantwell won her first Senate term in another squeaker of an election. So Washington state is not as dark blue as, say, New York.

In any case, Cantwell still lacks the 50% level of support below which incumbents must be a little nervous about their staying power. Those concerns may be eased a bit by the state's general preference for Democrats and the unfriendly environment for Republicans nationally at this time.

Senator Cantwell is viewed favorably by 60% of likely voters, a three-point gain over our previous survey. She is viewed unfavorably by 35%, another improvement.

McGavick is viewed favorably by 37%, unfavorably by 32%. Thirty percent (30%) don't yet have an opinion of him. Both of these numbers are a little worse for McGavick than those of our last survey.

Governor Christine Gregoire is viewed favorably by 57% of all voters. In addition, 57% of voters approve of the job she is doing as governor.

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