DAYTON, Ohio — Tens of thousands of military service members attempting to vote by absentee ballot in recent years haven’t had their votes counted because of various problems with the system, according to authorities that track voter participation.

The Military Voter Protection Project, an organization founded by a Navy Reserve member who previously was a Justice Department lawyer, is promoting efforts to ensure that the votes of all military members are counted.

“The problem has always existed, given the high degree of mobility of our fighting forces,” said Eric Eversole, founder and executive director of the Military Voter Protection Project, a nonprofit organization based in Washington, D.C.

But the issue is a bigger concern during a presidential election year with a military force totaling more than 3 million, including active-duty and reserve forces.

In 2010, of the approximately 2 million military and overseas voters accounted for in data reported by the states to the Election Assistance Commission, only 4.6 percent of those voters were able to cast an absentee ballot that counted, according to the Military Voter Protection Project’s analysis of that data from the federal Election Assistance Commission, which tracks participation in voting. That compared with 5.5 percent in 2006, which was also a midterm election, the organization concluded.

The overall national voter participation rate for the 2010 election was 41.6 percent, authorities said.

The frequent movement of some military members and the difficulty that state election authorities have in maintaining contact with them undermines the ability of deployed troops to vote, Eversole said.

Military voters who didn’t request absentee ballots, absentee ballots that were sent to the wrong addresses, ballots that were lost in the mail or delivered too late to be counted contributed to the problem, authorities said.

Eversole’s organization has begun the Heroes Vote Initiative to form partnerships with local military and veterans groups, as well as state and local election officials, to make military voters a priority in this year’s elections.

The Help America Vote Act of 2002 required states to report to the Election Assistance Commission on participation in voting, including balloting by U.S. military and overseas voters.

In 2009, Congress enacted the Military and Overseas Voter Empowerment (MOVE) Act, which requires states to transmit validly requested absentee ballots to those military voters no later than 45 days before a federal election, unless the state has been granted a “hardship waiver” by the Defense Department for that election. The 2009 law also requires states to use electronic delivery mechanisms for ballots, such as fax transmission, email or online delivery.

Ohio, Florida, Texas and Virginia are among states that are using tracking numbers to allow military members to track whether their ballots were received by local election boards back home, Eversole said. The tracking numbers are similar in concept to those that consumers use to track movement of express delivery packages.

Since 2010, the Defense Department provides a special label, called “Label 11-DOD,” that provides uniformed service members with express-mail priority delivery of their ballots through the military and U.S. mail systems. That label also allows tracking of the mail’s movement, said Ken Warford, the Defense Department’s deputy director of voting assistance.

“You always wondered if your votes were being counted,” said Pam Strickler, director of military affairs for U.S. Rep. Steve Austria, R-Ohio.

Strickler said that was a concern for her and her husband, James “Jay” Strickler, a retired Air Force colonel who is a former vice commander of Wright-Patterson Air Force Base, when he was stationed in England and Germany during the 1980s and ’90s.

Ohio Secretary of State Jon Husted said he has made it a priority to properly handle and count military absentee ballots, after having heard concerns from parents of military personnel during his 2009-10 campaign for office. Husted has told county election boards that it would be considered grounds for removal of board members if their agencies should fail to electronically send out absentee ballots 45 days prior to an election, to all military voters who filed valid applications by Jan. 1 of that year or 90 days before the election (whichever is earlier).