Most of the organizations, but not all, have thrown their weight behind the Democratic senator from Illinois. Those that did not have remained neutral. McCain has not been endorsed by any of the unions and associations contacted in a Federal Diary survey.
Those that did endorse said Obama is the better candidate for workers.
"As federal employees, our members have witnessed first-hand the devastating impact of the Bush administration's misguided policies, but with Senator Obama, we can right the direction of this country," John Gage, president of the American Federation of Government Employees, said when the union made its endorsement in the primary.
That sentiment was common among unions representing rank-and-file workers, including the National Federation of Federal Employees, the National Treasury Employees Union, International Federation of Professional and Technical Engineers, the American Postal Workers Union, the National Association of Letter Carriers and the Professional Aviation Safety Specialists.
In addition to those endorsements, this is the first year "where there is a clear partisan preference among campaign contributors who work in the federal government," according to the Center for Responsive Politics.
Justice Department employees gave more -- $268,600 -- to Obama than those in any other agency from January 2007 through August, according to the center. McCain got $97,400. At $127,300, Defense Department staffers were at the top of the list of federal employee contributors to McCain. They gave Obama $92,240.
Organizations representing senior-level staff and foreign service officers chose not to endorse. The American Foreign Service Association, for example, is fierce in its determination to shun partisan affiliations.
"We want to avoid that as much as we can," said President John Naland.
It does have a political action committee that contributes to members of Congress, however. But it is a strictly bipartisan operation. Naland said the PAC's bylaws require it to give equally to Republicans and Democrats.
The Senior Executives Association also is nonpartisan. Like the National Council of Social Security Management Associations, the Professional Managers Association and Federal Managers Association, the executive group believes "that posture better enables us to work effectively with both parties," President Carol A. Bonosaro said.
"Further," she added, "it is reflective of the role of a career executive, namely, to work to the best of his or her ability to enable any and every administration to be successful, and to do so irrespective of their personal political views."
For a union, endorsing a candidate "is a calculated risk," said John M. Palguta, a vice president of the Partnership for Public Service. "If they back the losing team, that does not endear them with the winning team."
But the unions believe that they have nothing to lose by backing Obama because McCain's record makes it clear that he doesn't support or respect federal workers, said Colleen M. Kelley, president of the National Treasury Employees Union. As evidence of that, Matthew S. Biggs, legislative director for the International Federation of Professional and Technical Engineers, noted that neither McCain nor any of the Republican primary candidates responded to questions on issues important to the union's members. All of the Democrats did.
The National Active and Retired Federal Employees Association does not officially endorse, but it has a political action committee that "makes campaign contributions to federal-friendly lawmakers," said Dan Adcock, the group's legislative director.
Democrats make up 60 percent of the candidates in the partial listing that Adcock provided of those receiving contributions from the association's PAC.
Time to Vote
In other election-related news, Reps. James P. Moran Jr. (D-Va.) and Tom Davis (R-Va.) asked the Office of Personnel Management to give federal workers an additional two hours of excused absence to vote on Tuesday.
In a joint letter to Michael W. Hager, acting OPM director, the Northern Virginia congressmen said an expected record turnout, plus changes in election laws could lengthen the time it takes to vote.
"We are concerned that federal workers may face the prospect of not voting or violating current federal leave requirements," they said. "Additional time for excused absence beyond the current three hours would go a long way toward relieving federal employees of this dilemma."