The League of Conservation Voters launched a direct-mail program Wednesday to assist Democratic Rep. Edward J. Markey in the Massachusetts special election for Senate.

With just three weeks left, the group announced it is spending almost $400,000 to highlight Markey’s leadership on environmental issues and the positions of Republican nominee Gabriel Gomez — which the LCV labels as “extreme.”

The first mail piece lands at homes this week. The glossy paper states that “no one has fought harder than Ed Markey” for clean-energy jobs and reducing the dependence on foreign oil. It also hits Gomez as a “Wall Street insider” and accuses him of being “in the pocket of Big Oil.”

A release from the LCV, a significant player in Senate races, states that it made more than 430,000 voter contacts during the primary while spending some $850,000 on a field program to support Markey.

Markey and Gomez are both on TV for the final sprint to the June 25 election. They are set to debate Wednesday night for the first time.

Rothenberg Political Report/Roll Call rates the race Democrat Favored.