Mayor Mike McGinn suffered a couple of stinging setbacks today when a major environmental group and the Seattle Chamber of Commerce both endorsed state Sen. Ed Murray for mayor.

“This a big blow to the mayor and a big win for us,” said Dean Nielsen, a political consultant who is heading up the newly-created People for Ed Murray, an independent campaign expenditure committee.

“We are blessed to have several mayoral candidates who hold strong environmental values, but Ed Murray is the clear choice to be Seattle’s next mayor,” said Brendon Cechovic, executive director of Washington Conservation Voters .

Cechovic added, in an interview with Seattle Weekly, “I think McGinn will be surprised.”

Asked what factors may have hurt the mayor in not getting the group’s stamp of approval, Cechovic said, “When it came to leadership, building coalitions and valuing compromise, we thought Ed Murray was the superior candidate.”

As expected, McGinn has already won the endorsements, as he did four years ago, of the other two influential environmental groups, the Sierra Club and the Cascade Bicycle Club, but failing to win WCV’s nod could have electoral consequences. The group spent some $750,000 in independent expenditures on behalf of Jay Inslee in the 2012 campaign and also recruited hundreds of volunteers to ring doorbells and make phone calls.

Cechovic said the group, which endorsed former Mayor Greg Nickels in the 2009 primary, then stayed on the sidelines in the general election, has not yet determined what resources it will devote to Murray.

“But it will be more than just an endorsement. We are in this to win it,” he said.

Murray also won the backing of the Civic Alliance for a Sound Economy (CASE), the political arm of the Seattle Metropolitan Chamber of Commerce.

“Senator Murray is endorsed for his visionary leadership, his commitment to fair and predictable regulation and his ability to bring together broad bipartisan coalitions around complex and groundbreaking issues, from transportation to marriage equality,” Maud Daudon, president and CEO of the Chamber said in a statement. “His political experience and achievements are invaluable in moving a regional vision forward.”

In ‘09, the Chamber endorsed T-Mobile executive Joe Mallahan over McGinn..

It is hard to gauge how much cache a Chamber endorsement carries, but Murra is certain to use it to make the case that he may be a good liberal and all, but can also be a friend to the business community.

Though McGinn has made serious inroads with the business establishment and certainly with the major property developers (see Paul Allen’s real estate firm Vulcan and South Lake Union), his veto of an aggressive panhandling measure sponsored in 2010 by Council member Tim Burgess.