Clint Didier has yet to concede the Washington Senate primary to Sen. Patty Murray (D) and Republican Dino Rossi, who finished well ahead of the tea party candidate in Tuesday’s “top two” contest. But an endorsement may in fact be on the horizon.

“We may have an announcement or something yet today,” Didier spokeswoman Kathryn Serkes said Wednesday. “Clint would like nothing more than to support Dino Rossi. But he takes this endorsement seriously, and a half-hearted or lip-service endorsement won’t be meaningful to his supporters.”

The Seattle Post-Intelligencer reported that “Didier told KOMO Radio in Seattle Wednesday he’d first like to see Rossi sign a pledge not to add or increase taxes.”

However, in a message to supporters posted on his campaign website Wednesday, Didier left out any hint of an endorsement: “While I may not be your official representative in the ‘other Washington’ this time, I won’t betray that trust. … I’m going to make sure that your voices aren’t drowned out as we head into the election. I promise my supporters that I’ll be with you all the way to Election Day — and beyond.”

Despite the lack of concession or an endorsement of Rossi in the message, Didier is in fact considering endorsing him in a show of unity, though the two camps had not talked as of Wednesday afternoon.

The primary campaign was testy and included attacks against Rossi through the eve of Tuesday’s election. Didier received early support from former Alaska Gov. Sarah Palin, but Rossi doubled him in fundraising and received instant establishment support after jumping into the race in May.

Didier questioned Rossi’s conservative credentials during the primary, but Rossi beefed up by unleashing a list of well-known conservative backers including Sens. Jim DeMint (R-S.C.) and Tom Coburn (R-Okla.).

With the secretary of state’s office still tabulating primary votes from the mostly mail-in election, Murray and Rossi are assured spots in the general with 46 percent and 34 percent apiece. Didier finished with 12 percent.