Defense Secretary Robert Gates circulated a letter to military leaders Tuesday detailing the implementation for repealing the controversial “don’t ask, don’t tell” policy, offering the latest push to end the policy this year.

“To be successful, we must understand all issues and potential impacts associated with repeal of the law and how to manage implementation in a way that minimizes disruption to a force engaged in combat operations and other demanding military activities around the globe,” Gates wrote. “Should Congress take this action, strong, engaged and informed leadership will be required at every level to properly and effectively implement a legislative change.”

The letter’s release Tuesday comes on the eve of a scheduled news conference in which Sen. Joe Lieberman (ID-Conn.) will officially introduce legislation that would repeal the policy that bans gays from serving openly in the military. President Barack Obama called on Congress to repeal the policy during his State of the Union address earlier this year, and he tapped Lieberman to lead the charge on Capitol Hill.

The chances for passing repeal legislation this year remain unclear and would require Republican support. Lieberman has so far been unable to secure a GOP co-sponsor to his legislation, but advocates of the policy change hope Gates’ move Tuesday might prompt at least one Republican to sign on.

Gates’ letter is part of the yearlong review the Pentagon has launched to look into the effects of rolling back the policy implemented in 1993 under President Bill Clinton. The secretary announced the implementation plan at a hearing last month before the Senate Armed Services Committee, during which he and Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, offered compelling testimony supporting Obama’s call for a repeal.

Gates’ letter was sent to the secretary of each military force, the undersecretary for personnel and readiness, the Defense Department’s general counsel and Mullen. In it, Gates encourages the military leaders to reach out to all ranks and ages to gauge the effect a ban of the “don’t ask, don’t tell” policy would have, and to report their findings by Dec. 1 of this year.

“To effectively accomplish this assessment, I believe it essential that the working group systematically engage the force,” Gates wrote.