When Republican gubernatorial hopeful Charlie Baker makes a campaign in Springfield today, he’ll be joined by an unexpected supporter: City Councilor Tim Rooke, a life-long Democrat.

Rooke tells the Advocate that he’s never before endorsed a Republican, but was inspired to cross party lines in support of Baker’s call for ending government waste. In particular, Rooke is steaming over the decision to move the Springfield School Department to the vacated former federal building on Main Street, without seeking competitive bids for other sites. Rooke calls that move—which was supported by both the Patrick administration on the state level, and the Sarno administration on the city level—a “$12 million mistake,” to be borne by the taxpayers.

Rooke will join Baker on the steps of Springfield City Hall today at 12:30.