Leaders of gay civil rights groups and LGBT veterans organizations are optimistic about the next two-week time period, one that may well determine whether Congress moves forward this year to repeal the federal statute commonly referred to as “Don’t Ask, Don’t Tell,” that has banned openly gay people from the military for nearly 17 years.

But that is despite some disappointments.

Some were disappointed last week when the White House sent to Congress its policy recommendations for the National Defense Authorization Act for Fiscal Year 2011 that did not include any request to repeal “Don’t Ask, Don’t Tell” (DADT). That added to the stinging disappointment a week earlier when the White House issued a statement saying, “implementation of any congressional repeal will be delayed until the DOD study of how best to implement that repeal is completed.” The statement was issued just hours after Associated Press reported that Defense Secretary Robert Gates had sent a letter to House Armed Services Committee Chairman Ike Skelton saying that he and Joint Chiefs of Staff Chairman Admiral Mike Mullen “strongly oppose any legislation that seeks to change this policy prior to the completion” of a Pentagon study, expected in December.

“It didn’t help,” said Aubrey Sarvis referring to the Gates letter. Sarvis, head of the Servicemembers Legal Defense Network, said the Gates letter may well have raised “concerns” for some members of Congress, nervous about taking a controversial vote in an election year. But Gates’ objections “didn’t take us down before the count,” he said.

“It [only] made the task more difficult.”

This week, repeal proponents lost the support of a key Democrat on the Senate Armed Forces Committee when Nebraska Senator Ben Nelson told the Washington Blade that he would vote against any repeal effort next week when the committee considers the defense authorization bill.

Nelson told the Blade that he wants “to follow with the advice and the suggestions of Secretary of Defense Gates to have the study that is underway right now before we make that final decision—because it’s not a question of ‘whether,’ it’s a question of ‘how.’”

But Nelson and other members of Congress are also facing intense lobbying from proponents of the repeal. ?Last week, the Human Rights Campaign and Servicemembers United, an organization of gay veterans, coordinated a two-day lobbying effort spearheaded by former LGBT military officers and enlisted personnel. SLDN and 60 other groups signed on as co-sponsors of the effort.

More than 350 veterans from over 40 states were in Washington, D.C., May 10 and 11 to lobby members of Congress as “a final push before the critical defense authorization bill markup periods this week and next week,” explained Alexander Nicholson, executive director of Servicemembers United.

“It was largest number of veterans ever hitting the Hill at once to lobby” on DADT, said Nicholson, “sending a message overall about their seriousness and intensity of demanding repeal this year.”

One of those veterans was John Affuso, who is now an attorney in Boston. Affuso said he flew to Washington specifically to lobby Republican Senator Scott Brown (R-Mass.), a crucial member of the Senate Armed Services Committee.

Brown, elected in January to fill the seat left vacant by the late Edward M. Kennedy’s death, is one of five senators whose votes repeal advocates say they need to ensure repeal provisions are approved in the Senate.

The four other members of the Senate Armed Forces Committee, all Democrats, are Senators Evan Bayh of Indiana, Bill Nelson of Florida, Jim Webb of Virginia, and Robert Byrd of West Virginia.

“I told [Brown’s] legislative aide,” Affuso said, “that the senator and I have a couple of things in common, the same law school (Boston College) and the National Guard. The difference is that he went on to have a career as a Judge Advocate General (JAG). I ruled that out for two reasons. First, I couldn’t see how I could serve under the policy even as a signalman that would have been problematic personally. Second, after law school, as a JAG officer, I couldn’t throw people out.”

Senator Brown has not yet made clear his position on lifting the ban. But shortly after being sworn in, he voiced concern about a repeal as a “social experiment.”

Brown’s vote in committee is an important one and could be a defining moment as he seeks to carve out national role in the Republican Party at the same time he tries balancing his duty to represent the generally gay friendly state of Massachusetts.

Bay State repeal advocates have left nothing to chance. An HRC-hosted LGBT veterans panel and discussion, also sponsored by MassEquality, was held in Boston’s Historic Faneuil Hall on Wednesday, May 19, aiming was to win over Brown’s support.

“I don’t know his mind,” said Joe Solmonese, HRC president. “But if a guy like him stepped forward and said [repeal] is the right thing to do and to hell with the consequences” that would be a an example of real “leadership” that, “if handled the right way, he could still have a place on the national stage.”

In addition to lobbying members of Congress, gay veterans also participated in special policy briefings with White House officials and staff members of the Pentagon’s DADT study group.

And repeal proponents’ optimism was also bolstered by a letter to President Obama from the grandson of former President Harry Truman. It was Truman who issued an executive order on July 26, 1948, which set in motion the racial integration of the armed forces.

“There are strong parallels between desegregation of the military and the debate over ‘don’t ask, don’t tell,’” wrote Clifton Truman Daniel, in the open letter to the president, published by a number of newspapers.

“It was not easy,” Daniel wrote. “[My grandfather] faced fierce opposition from inside and outside the military.” Daniel voiced “hope” that President Truman’s “example” would help President Obama lead “with the same courage and conviction.”