Massachusetts State Sen. Ben Downing (D) will not run for Senate, bowing to the overwhelming Democratic party push behind Rep. Ed Markey.

"I know that every consideration – especially financial – must be made before a race of this type is undertaken," Downing said. "After considering every aspect of a possible campaign, I have determined that I will not be a candidate for the U.S. Senate in the upcoming special election.”

The League of Conservation Voters just endorsed Markey for the seat currently held by Sen. John Kerry (D), joining the Democratic Senatorial Campaign Committee, Vicki Kennedy, Rep. Barney Frank and Kerry himself in backing the congressman. 

Reps. Michael Capuano and Stephen Lynch have yet to announce their intentions. Attorney General Martha Coakley has said she will not run for the seat. 

Assuming Kerry is confirmed as secretary of state, a special election will be held later this year. Frank is hoping that Gov. Deval Patrick (D) will appoint him as a placeholder in the interim.