According to MassLive.com:
Republican Sean Bielat announced Wednesday that after mulling for less than a week, he will not join in the special election to replace Secretary of State John Kerry in the U.S. Senate.
The two-time congressional candidate said in an email to supporters that his candidacy never left the exploratory phase, although he recently filed papers with the Federal Election Commission as well as an official statement of candidacy for the Senate seat.
“The numbers looked pretty good and the fundraising went well so I think we could have mounted strong campaign but now is just not the right time for us,” Bielat said. “After spending some time thinking it through with Hope, we decided running another campaign just wasn’t a good fit for our family right now, given the age of our one and two year old children and their needs.”