CHICAGO (CBS) — On Monday, CBS 2 learned that mail-sorting machines are being taken out of service at Chicago’s Main Post Office west of the Loop and also at O’Hare International Airport. The claim comes from the president of a postal union in Chicago.

Democrats said it is part of President Donald Trump’s nationwide effort to slow voting by mail.

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CBS 2’s Jim Williams spoke to Keith M. Richardson, president of the American Postal Workers Union Local 0001 representing postal drivers and clerks. At Chicago’s Main Post Office, the Cardiss Collins Post Office Building at 433 W. Harrison St., Richardson said the bosses have taken all four mail-sorting machines offline.

“My members are disheartened by what’s going on in the Postal Service,” Richardson said.

Richardson said a fifth sorting machine is also being dismantled at O’Hare.

“Well, it could slow down operations,” he said. “I mean, if you have an abundance of mail or less equipment, it’s going to take more time to process the mail that’s on hand.”

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Democrats charge President Donald Trump and his Postmaster General, Louis DeJoy, are trying hamper mail-in voting.

The president is a critic of voting by mail – saying, without evidence, that it’s fraudulent. Last week, President Trump said mail-in voting would help Democrats.

The Postmaster General said he is simply trying to reform the system.

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As the Democratic National Convention begins, Mayor Lori Lightfoot, in a video conference, decried what she called an assault on democracy during a time when more people want to vote by mail during the pandemic.

“Vote-by-mail is the lane that we need to run in, and that’s why we cannot allow this administration to undermine the Postal Service in the way that it’s clearly trying to drive the Postal Service to its knees,” Mayor Lightfoot said.

The Chicago Board of Elections said it has already seen a big increase in the number of Chicagoans who want to vote by mail – 250,000 applications so far and counting. Board of elections Chairwoman Marisel Hernandez urges voters to mail in their ballots as soon as they get them.

“When you get this vote-by-mail application, within 24 hours, you know, sit down at the kitchen table, fill it out, put it back in the envelope we sent to you, and put it in the mail,” Hernandez said. “It’s a postage-paid envelope. You don’t have to worry about anything.”

Get the ballots in early, Hernandez said.

As President Trump takes heat from congressional Democrats, who are heading to back to Washington for hearings on what’s happening at the Postal Service, President Trump tweeted, “Save the Post Office.”

If you want to vote my mail, you have to apply. You can do it online.

Williams spoke to a voter who lives in West Chatham who said, “I haven’t received my ballot,” but said she had not applied to vote by mail when asked. Again, you have to apply.

The ballots will start being mailed in late September.

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