State Rep. Dan Winslow (R) is exploring a bid in the special election for the open Massachusetts Senate seat, making him the first Republican candidate to enter the race.

“Today I’m taking the necessary steps to form an exploratory committee to test the waters for the U.S. Senate," Winslow said in a statement. "We need to fix a broken Washington where progress is being hampered by partisan gridlock. If we continue to elect the same Washington politicians, we can not expect different results.” 

Former senator Scott Brown, former congressional candidate Richard Tisei, former governor Bill Weld, former lieutenant governor Kerry Healey, and Romney’s oldest son, Tagg Romney, have all passed on the race for Secretary of State John Kerry's seat.

On the Democratic side, Reps. Edward J. Markey and Stephen F. Lynch are vying for the nomination. The primaries will be held on April 30, and the special election on June 25. Gov. Deval Patrick (D) has appointed his former chief of staff, Mo Cowan, as a placeholder.

Winslow, a former district court judge, was the chief legal counsel to both former governor Mitt Rom­ney and Scott Brown's 2010 campaign. In the state house, he represents the same Norfolk district Brown once did. He's known for his aggressive use of social media and willingness to tangle with liberals on the blog Blue Mass Group. Last year he delivered ten jars of marshmallow Fluff to the statehouse -- with his ideas on how to trim "fluff" out of the budget attached.

"We have a national brand that has suffered damage in the last election cycle," said Winslow in an interview, describing himself as a libertarian-leaning, moderate on social issues and prudent on fiscal matters. "Massachusetts Republicans are a different breed of cat ... this election represents a historic opportunity for Republicans to show who we are and what we're about."

In a statement, Massachusetts Democratic Party Chairman John Walsh called Winslow one of Romney's "apologists and political attack dogs" who "is more interested in grabbing headlines than getting work done for the people of the Commonwealth."