The deadline for states to send absentee ballots to deployed service members has passed, and congressional offices that represent large military populations said they haven't received any complaints so far this year.

Military voters often struggle to navigate the absentee voting process because of their frequent moves and deployment overseas. The Military and Overseas Voter Empowerment Act, passed in 2009, was supposed to eliminate challenges troops faced in voting absentee by using more technology to vote and implement a "more robust" registration system for military voters, according to the Military Voter Protection Project.

But spotty implementation caused troops to still face issues in the 2012 election. For example, of the 126,251 active-duty troops and souses in Virginia, only about 1,746 requested an absentee ballot ahead of the last presidential election, according to data compiled by the group.

About two-thirds of military members need to vote by absentee ballot, the Military Voter Protection Project said. Absentee ballots are required to be sent to military and civilians working overseas 45 days before federal elections, meaning they all should have been mailed by Sept. 24, according to the Defense Department.

A Defense Department spokeswoman said it's up to the Department of Justice to track and enforce compliance with this deadline. The Department of Justice declined to comment on whether any ballots had missed this cutoff.

But lawmakers with large military communities in their districts said they have received no reports of issues with the absentee ballot process yet this year.

Rep. Marsha Blackburn, R-Tenn., whose district includes Fort Campbell, said her office has yet to hear from any service members this year who did not receive their absentee ballot on time.

"We in Tennessee are so very fortunate to have a capable election commission in each of our 95 counties. While some areas do experience problems, we have not had any complaints this year," she said in a statement.

Rep. Sanford Bishop, D-Ga., said his office "has not been made aware of any irregularities in the absentee ballot process for service members."

"I recommend to any service members encountering obstacles toward casting their ballot from their place of duty to immediately contact the voting assistance officer appointed within their unit of assignment, as well as their member of Congress and state's board of elections," Bishop said.

In 2012, a plane carrying mail heading to Afghanistan may have destroyed absentee ballots. A military spokeswoman said she is not aware of any accidents or incidents that may have resulted in lost or destroyed ballots for 2016.

In the most recent Military Times poll of service members, 40.5 percent of respondents favored Donald Trump, followed by 27 percent backing Gary Johnson and 20.6 percent planning to vote for Hillary Clinton. The poll, released Wednesday, gathered responses from 2,500 active troops and was conducted Oct. 12-14.