DeJoy Tells Senators Election Mail Will Be Delivered ‘Fully and on Time’

Carrying out the changes had been rockier than expected, he conceded, but Mr. DeJoy initially played down the costs. Pressed later on by Senator Rob Portman, Republican of Ohio, with the “heartbreaking stories” of Americans, including veterans, missing medicine because of those delays, he offered a measured apology.

“Senator, we are working here feverishly to get the system running at stability and also to hire more workers to handle the delivery process,” he said. “We all feel bad about what the dip in our service, the level it has been.”

Lawmakers in both parties were most concerned that the post office might not be able to handle a crush of mail-in ballots for the 2020 election in the middle of a pandemic.

He said the agency planned to send a letter to every American next month explaining its plans for safely transmitting ballots, and he assured Senator Mitt Romney, Republican of Utah, that “we will scour every plant each night leading up to Election Day” for ballots.

Senator Gary Peters of Michigan, the top Democrat on the Senate homeland security panel, told Mr. DeJoy that his decisions “have cost Americans their health, their time, their livelihoods and their peace of mind.”

“I believe you owe them an apology for the harm you have caused,” Mr. Peters said.

And grilled by Senator Jacky Rosen, Democrat of Nevada, Mr. DeJoy refused to commit to providing transcripts or minutes of all closed, nonpublic board of governor meetings, as well as an analysis of the effect of the changes on veterans, working families and older Americans. Instead, he promised to provide “the analysis that designed the truck schedule that I directed.”

Mr. DeJoy’s defense on Friday came a day after the former vice chairman of the Postal Service’s board of governors offered lawmakers a scathing account of the agency under the Trump administration.