"The reason he does it is because the more people hear something like that, the more they're discouraged to vote," Pelosi said during an interview with CNN's Brianna Keilar. "It's a way to suppress the vote."
Pelosi noted that Trump's tweet on Thursday floating the idea of delaying the election came on the same day as the funeral for the civil rights legend Rep. John Lewis (D-Ga.).
"At the same time as we are burying a hero of voting rights, our democracy, he goes out and says something beneath the dignity of the White House. But he does that almost every day, beneath the dignity of the presidency," Pelosi added, The Hill reported.
There is no evidence that either absentee or mail-in ballots increase voter fraud. It's also highly unlikely that all voters will choose to cast their ballots by mail in November.
Trump himself has voted absentee, including for the GOP presidential primary earlier this year.
Furthermore, Trump does not have the authority to change the election date. Election Day is always the Tuesday after the first Monday in November, as established by federal law. Only Congress would have the power to change the election date, and it's highly unlikely that the Democratic-controlled House would do so at Trump's behest.
Top Republicans in Congress also pushed back on Trump's trial balloon on Thursday, including Senate Majority Leader Mitch McConnell (R-Ky.).
Trump also swiped at former President Obama, who delivered a eulogy at Lewis's funeral in which he said that "there are those in power who are doing their darnedest to discourage people from voting," including by targeting minorities with restrictive voter ID laws and closing certain polling locations.
Former Presidents Bill Clinton and George W. Bush also spoke at Lewis's funeral on Thursday.
Trump, who clashed with Lewis in 2017, notably did not attend the funeral or pay his respects while the late congressman laid in state in the Capitol earlier this week.
"I did much more for minorities than he did and if you look at our numbers prior to the play coming in and those numbers will soon be back, you will see I did a much better job than Obama did, by far, for African Americans, for Asian Americans, for women, for any group you look at, far better than Obama did," Trump said to reporters at the White House on Friday.
Pelosi later appeared to take a dig at Trump's weight, questioning whether there was "an ounce" of decency "in that big frame."
"Three presidents praised John Lewis," Pelosi said. "You would think that there would be an ounce, in that big frame, of decency to say something about the importance of voting in our democracy, instead of criticizing somebody else's eulogy."
Back in May, Pelosi drew pushback when she described Trump as "morbidly obese" while criticizing his decision to take a drug that has not been proven to prevent or cure COVID-19.
"I would rather he not be taking something that has not been approved by the scientists, especially in his age group and in his, shall we say, weight group, morbidly obese, they say," Pelosi said on CNN at the time.