The Pennsylvania Supreme Court recently ruled that ballots must be postmarked by Election Day and arrive by Nov. 6, but Republicans argue that ruling violates federal law.
Many Republicans support legislation that would move up the deadline to apply for a mail-in ballot and eliminate drop boxes, but Democrats say that would make voting more difficult.
Most of those surveyed, including 200 in Pennsylvania, disapprove of how Trump responded to the pandemic.
President Donald Trump accused Democrats in Luzerne County of "trying to steal the election," but the county is under Republican leadership.
With a surge of mail-in ballots expected due to unease about voting in-person during the coronavirus pandemic, many states may not be able to declare a winner for days, if not weeks, which means the US.
Activists with Students Demand Action are working to register 100,000 new young voters before the November election.
The court, which ruled last week that mail-in ballots can be counted if they arrive at local elections offices by Nov. 6, refused a request from Republicans to put its order on hold.
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