Almost 70 percent of the 258,000 service members overseas during the last presidential election cast ballots, compared with 51 percent of the general public and 37 percent of U.S. civilians overseas, said Charles Abell, principal deputy to the undersecretary of defense for personnel and readiness.

Of those who didn't vote, almost 22 percent said they never received ballots, according to Pentagon research, and 7 percent said they got them late. Twenty-six percent said they didn't know how to get a ballot.

Military voting problems created an uproar in the 2000 election when some ballots were rejected in Florida, where George W. Bush's razor-thin margin of victory gave him the presidency after an extended legal battle. Several hundred absentee ballots from troops abroad were thrown out in the state for lack of postmarks, as required by state law, or other flaws such as no signatures.

Laws for casting ballots from abroad differ from state to state, and the mailing process itself can be daunting.

For instance, while almost three months remain until the Nov. 2 election, the process for voters overseas starts in September.

In its awareness program this year, the Pentagon is stressing two key weeks, the first of which is Sept. 3 to 11.

"If you have not requested your ballot, or you have not registered for this election yet, you should do it, you must do it, during this week," Abell said.

That will allow enough time for the request to get to the voter's local precinct, for the precinct to send back the empty ballot, and for the service member to send it back completed, he said.

The week of Oct. 11 to 15 is the latest overseas voters can safely send in their ballots.

"This is sort of like the Christmas mailing season," Abell said.

If ballots are mailed by then, "even from the remotest part of the world to the remotest part of the United States, the ballot material should get back to the local voting official in sufficient time to be counted," he said.

The military has trained officers to help troops, has worked with states to increase from 23 to 32 the number that permit fax delivery of blank ballots, and is providing an online version of the federal ballot application, which is accepted by 53 states and territories, Abell said.

Since 2000, officials have worked with the federal postal service and with the states to improve logos and designs on balloting materials so that they are better recognized in post offices and election offices.

Officials also have worked with the postal service to get expedited handling and have issued proper postmarking machines to military units, Abell said.

The Defense Department is responsible for voting for all Americans overseas. Abell said that among the potential absentee voters, 1.4 million are military members and 1.3 million their dependents. Another 100,000 are federal civilian employees, and 3.7 million are U.S. civilians not affiliated with the government.