The ballot drop boxes in Washington and Oregon both have fire suppression systems that are designed to activate when the temperature inside reaches a certain point, coating ballots inside with a fire-suppressing powder.
For unknown reasons, the system failed to prevent the destruction of hundreds of ballots in Vancouver, just across the Columbia River from Portland.
We actually do have laws federally to protect voters from disenfranchisement. There are often lawsuits about polling locations, hours of voting, and number of drop boxes. One side is definitely always trying to make it harder to vote, specifically on contested areas.